As usual, there is a long story involved so I will hit you with the questions first. There's no need to read the whole story unless you have plenty of time.

1989 TP Sedan, Carby, Auto:

(1) Where do the discharge weight and ball go in the carburettor and what effect does it have if they are missing?

I noticed them when disassembling the carby on a previous occasion but didn't come across them today. Today I only removed the top cover to get at the float chamber. I didn't separate the main body from the lower (throttle body) section. I always hold the carby inside a big plastic storage box when disassembling to avoid losing things but anything's possible.

(2) Where would you suggest trying to buy a new float needle and seat plus the discharge weight and ball if I've lost them?

Tamworth is my nearest big town. They have a Repco, Bursons, Supercheap and Autobarn. I know Mitsubishi no longer stock 1st or 2nd gen. parts. Central Coast Carburettors in Gosford would probably have the parts but that would have to be mail order.

Now the story:

My TP sedan has been plagued with intermittent rough running for a couple of months now. I really should write up my adventures trying to find and fix the problem. These include removing the head (with manifolds and camshaft in place) and replacing the head gasket. A couple of weeks later, I also removed the inlet manifold and replaced it with a brand new one. I also fitted a new aluminium radiator to keep temperatures down.

I removed and disassembled the carby thinking it might be contaminated with carbon granules again. I had that problem before but this time it was clean.

The engine usually runs reasonably well when first started but rough when hot except under full throttle. When I go to town for shopping, I have trouble keeping it running at traffic lights and roundabouts. It feels like it is running on two cylinders.

Normally it starts on first hit of the starter, hot or cold but that has changed in the last couple of weeks. When cold, it now needs a couple of long cranking attempts before it fires.

Fuel consumption has been horrendous - averaging 15.6 litres per 100km for easy country driving. Disabling the automatic choke improved this only slightly. Eventually the fuel consumption has forced me to consider that the rough running may be due to the carby flooding intermittently.

Anyway, today I took the carby off once again. When I lifted it off the manifold, both the main and secondary throats had raw petrol at the bottom. I had to open the throttle butterflies to let it pour out. This was before disassembling anything.

I took the top cover off and had a look at the float, needle and seat. Mine is an 89 model so float height is not adjustable, not officially anyway. The needle and seat look worn but also the float seemed to be hitting its stops before the needle was fully closed.

I intend to replace the needle and seat but as I'm miles from anywhere, there is nowhere to buy parts and no way of getting them without a car, so I had to re-assemble the carby as is. A little judicious bending of the float bracket seems to have improved the seating situation slightly.

I now have it all back together and the engine seems to be running better, at least when cold. I won't know for sure how it goes when hot until my next trip to town on Thursday (150kms return).

you need a used carby


I dont know if a TR/TS carby will interchange
the TR/TS manual i have has a picture of
balls ,weight and springs
they go in the two holes next to the
nearest the accelerator pump (the two external pipes one on top
of each other)

the TP Repco kit may not have the ball and needle and seat

it always happens i threw away 3 carbies last month

in my info notes TM_TP on carbies has an exploded view
I have the numbers list on the original document
the ball and weight is 81 to 84
sorry i cant be more help
buffy

Thanks, magna buff. I've seen that exploded view and have a copy of it but it doesn't show their actual location in the carb. From your instructions, I can probably find where they go now. I guess they must be missing as otherwise they'd have fallen out yesterday. When I replaced the head gasket, I removed the head with inlet manifold, carby and exhaust manifold all still attached. My neighbour helped me lift it off and back on again. Of course we had to turn the whole thing upside down so I could clean the head and remove all old gasket residue before refitting it. The weight and ball probably got dislodged then and lost the next time I opened the carb up.

I've just spoken to Tamworth Carburettor Service but they've closed down and weren't able to help. There's a wrecker in Tamworth who might have a carby but I don't have money to throw around gambling that it may be better than mine.

The Repco carby kit is about $100 isn't it, but I thought that was only a gasket set? If it includes the float, needle and seat it may be worthwhile.

yes thats about the price

it wont have the seat just a needle

now the needle in my kit was for a TN
it had o rings and gaskets as well

no ball bearings weights float or springs

small ball bearing out of a bicycle might do

buffy

There are a few sellers on eBay with Mikuni carby repair kits for between $45 and $80. All those listed at present are for earlier models but they might have or be able to get the kit for mine as well. The kits seem to include the needle and seat but not the float and I don't know whether the discharge weight and ball are included. Still, at that price they'd be worth it for the gaskets, diaphragms and seals. At the rate I'm using fuel, it would pay for itself in a couple of weeks.

I just took the car for a run to see how it goes when hot. It is definitely not fixed. It is ok when cruising and goes well at full throttle but won't idle (flooding I think).

Edit: I was posting at the same time as you. You're right. I don't think they include the seat. I will contact one of the sellers and see whether they have kits for the 89 model. The way things are going, I'll have to go 2nd gen. It is getting too hard to find good 1st gens. Have to get some money together first. Thanks for all your help.

I have a carby from a TM magna. The needle & float valve kept leaking and causing flooding whenever we stopped. I was told that you couldn't buy a new needle & seat, so I bought a new Weber carbie instead - with a manual choke. You are welcome to have to original Tm carby if you think you can use it.

Another question, magna buff. My carby's float and needle assembly looks similar to the TR-TS one in the exploded diagram you referred to above. The needle is brass and its bottom section is spring loaded. Its top (where it seats) is cone-shaped (a flattish cone). The seat appears to be just cut into the plastic (i.e. just a conical top to the hole in part 52 in that same diagram). Does that seem right to you? I was expecting it to also be brass.

I have a carby from a TM magna. The needle & float valve kept leaking and causing flooding whenever we stopped. I was told that you couldn't buy a new needle & seat, so I bought a new Weber carbie instead - with a manual choke. You are welcome to have to original Tm carby if you think you can use it.
Thanks for the kind offer, erad. However it seems yours has the same problem as mine but the parts would be different. I think I'll get one of the carby overhaul kits off ebay and try to fix mine.

I noticed Weber and Empi (Weber clone) kits for Astrons on eBay. They are too expensive for me and mine's an auto which would complicate matters. I do have an EFI TP wagon that I use for parts. If I get desperate enough, I could do an EFI conversion from it to the sedan.

only plastic is the float itself
carbs are funny alloys and aluminium
with a stainless steel seat
brass for other bits

looking at both repair manuals
the floats all look the same over the models

Thanks, magna buff. I've been pondering why the float, needle and seat assembly seemed so sloppy yesterday when I don't recall it being like that on previous occasions. I think the brass part of the seat may be missing which is why I asked the question. No wonder it is flooding. I'm mystified how that could happen though. I'm not silly enough to lose something like that. Well I don't think so anyway.

I agree the floats look to be the same but according to my Haynes manual, the float height in TM and TN models manufactured prior to January 1988 was adjustable by means of shims fitted under the seat. Later models including the TP, TR and TS were non-adjustable. That means the seats are not the same and I need the one for TP or later. I'm going to Tamworth tomorrow and will check the wreckers there for a carby. It looks as if I'll need a used TP carby plus one of the repair kits. A TR or TS might do but I'm not sure so will play it safe. Thanks again for all your help.

might be contaminated with carbon granules again. I had that problem before but this time it was clean.

That would be from bits your charcoal cannister and they are charcoal granules.
Probably what has caused all your problems i had a TN with the same problem and left a lot of junk in the bottom of the fuel bowl that is very hard to remove so ended up getting another carby for that car.
Whatever you do with your carby make sure you block off the charcoal cannister hoses to the carby or it will happen again as it did with us until we found out where the granules were coming from.
We actually put another cannister on the car the first time and within six months it happened again. Not sure what causes it if it is a manufacturing fault or a backfire that goes down the hose and blows a hole thru all the mesh and grills in the top of the charcoal cannister that stops the stuff getting sucked into the carby.
If you have the time swap the EFI from your parts car and wiring harness plus ECU it will be worth it in the long run. Days work would do it even with pulling the dash. Vee

Firstly, yes I made certain the carbon granules can no longer get into the carby or anywhere else. That doesn't have anything to do with the current problem except that it forced me to remove, dismantle and clean the carby 3 or 4 times to get all the granules out of the system. In doing so, I may have lost the accelerator pump check balls and weight. I'm not 100% sure they are missing but didn't notice them last time I had the carby apart.

I just ordered off eBay a carby rebuild kit and, believe it or not, a float, needle and seat assembly. The latter is aftermarket, not genuine Mikuni, but brand new and identical to the original. I also arranged to buy a used carby from the wreckers at Tamworth for $85 but can't pick that up for two weeks because they are closed for hoildays.

Finally, I found a diagram of where the check balls and weight go (see below), so next time I open the carb up, I'll know where to look for them. I will report back again in a couple of weeks by which time I should have fixed the problem.

http://users.tpg.com.au/acheson1/images/carb.jpg

Just for interest, here's a pic of the head gasket I replaced. There's evidence of a leak from the water jacket to the rear of the block but otherwise less damage than expected.
http://users.tpg.com.au/acheson1/images/headgasket.jpg

Hiya Coldy,
1. needles and seats that dont seal are a pain. In the past I've not had much luck with polishing the seats. I have a few 2 and 4 stroke motors on various farm machines which dont get used much and the needles and seats are usually a problem with sticking shut or open after being left unused for some time. I have used cotton buds and kebab skewers to try to polish the seats with only limited success. I also have some diamond grinding paste which needs a lot of time to polish up a small area. I find the fuel can leave sticky deposits all over the float needles and this is not soluble in petrol; just needs a lot of rubbing to get the goo off. Its particularly bad with 2 stroke fuel. I find if a needle sticks it is because it is so light in weight and goo allows it to stick in the channel it runs in.
2. my magna was running rough and I rebuilt the vacuum motors (see my posts) After the rebuild it was running beautifully. HOWEVER, something has gone wrong. When cold it starts and runs like a dream: BUT when it gets hot, it starts to miss in an erratic kind of way. If I press the accelerator, it seems to come good momentarily. I have agonised over this and I am coming to the view that the problem may be the ignition module in the distributor. It was replaced only a few months ago. The car was always OK when cold but when warmed up it would stop firing few say a few seconds and then come good. It always recovered so that I could get home. The unit in the car was an after market one so the original Bosch must have failed at some point. I replaced the module with the same aftermarket brand ($50 at Repco). It is possible that the mounting screws for the module are not tight and I have to check this. it can happen with these modules that a particular design exhibits a characteristic failurre mode and I am forming a view that the module may have a characteristic where it works OK when cold but plays up when hot. Consider your problem may be ignition and not fuel. My problem with erratic running sounds and feels like fuel but the missing is i think too rapid in nature to be fuel, so I want to check ignition. I have noted that the tacho seems to respond exactly with the miss. Of course, any missing is a loss of fuel and your consumpton will increase. Mitsubishi make comment not to run the car if it's missing cos it will damage the catalytic converter.
Anyway, good luck. Check out my posts too cos there might be something there.
I will keep posting about my missing problem.

Hi Rumpfy, Thanks for your post and please do keep us informed of your progress.

My carby parts should arrive tomorrow or Friday, so I'll be able to work on it next weekend. For the check balls, I ordered some ball bearings from a bicycle shop on eBay. They come in packets of a gross (144). Since I don't know the required size, I bought a pack each of 1/8", 5/32" and 3/16". It seems silly that I'm getting 432 ball bearings when I only want two but they're cheap at under $5 a pack. The Mikuni check balls are probably metric but the size shouldn't be too critical provided they (a) don't fall right through and (b) don't jamb in either the tube or the orifice. I think I should err on the small side, if anything. I will probably have to make my own discharge check weight but I don't think that should be too difficult or critical.

Yes, I considered the distributor as a possible cause of the misfiring and it will be next cab off the rank if the carby is not the problem. I've read that, apart from the ignition module, another problem the distributor can have is that when the shaft becomes worn the pickup reluctor can touch, causing erratic coil triggering.

I took a look inside my distributor and ruled it out for the time being because (a) there are no visible signs of wear or debris inside and it is relatively low mileage (less than 100,000km). (b) the engine smooths out at full power. (c) I know for sure the carby is flooding. Until that is fixed, it is not possible to gauge how well anything else is performing.

Incidentally the slight adjustment I made to the float in the carby made quite a difference. It is still flooding at idle but on my last trip to town, fuel consumption improved from 15.6 litres per 100km to 10.9 litres per 100km.

Another possibility I've considered and perhaps you should too, is a faulty EGR valve. There's a good description here: http://www.ehow.com/about_5790592_egr-valve-failure-symptoms.html

Progress report:

The carby parts I ordered were delayed by holidays but arrived today. The float, needle and seat are identical to my originals but not as loose, so hopefully that will fix the flooding issue. The ball bearings I ordered separately haven't arrived but two ball bearings were included in the carby rebuild kit. As best I can measure with digital calipers, they are 4mm or 5/32" diameter. I guess those are the "check balls" that I need, so I will start work on the carby tomorrow.

The only part I don't have is the "discharge check weight". I will try to make one from the unthreaded portion of a 5/32" bolt after cutting off the bolt head and the threaded portion. Could anyone hazard a guess at the length of the original discharge check weight? Would 10mm be about right?

I took the carby off this morning and fitted the new float, needle and seat. I also replaced the accelerator pump diaphragm and the other small diaphragm which I think is for the mixture control valve. The accelerator pump discharge weight and the ball bearings for its inlet and outlet check valves had not been lost at all. When I located them and took them out, I found a few carbon granules in the accelerator pump inlet and outlet passages. I was previously unaware of those passages, so hadn't cleaned them before.

Anyway, it is all back together and seems to be running smoothly with no misfiring or vibration. I won't pronounce it fixed until I see how it performs under all conditions on my trip to town on Thursday but it looks hopeful.

Incidentally, the risk of losing the accelerator pump discharge weight and balls is not as great as I thought. When you take the top section of the carby off, the gasket usually remains stuck to the middle (plastic) section of the carby rather than the slicker aluminium top section. Provided it does that, the gasket prevents the discharge weight and outlet check ball from falling out.

The inlet check ball shouldn't fall out either because a cylindrical plastic plug that is a neat fit in the hole is pushed in after it. In the image below, the discharge check weight and ball are on the left. The discharge weight is approx 10.7mm long and 5.4mm diameter, made of brass and weighs approx 2 grams. That's the inlet check ball and plug on the right. Refer to post 12 above for a diagram of where they go.

http://users.tpg.com.au/acheson1/images/weight.jpg

Well, it still isn't fixed #@&%$#%. On my trip to town (75km each way), it ran well at first but seemed a little down on power on the hills. It was still running well when I arrived at the destination and pulled into the servo for fuel. Fuel cost of $26.70 works out at about 10.5 litres per 100 km, so almost back to normal. However, when I restarted, the engine was as rough as a dog, misfiring and vibrating badly. It continued like that everywhere I went for shopping, even after cooling off while parked. I stalled it a couple of times at the lights.

I stopped and took a look under the bonnet. Taking the ignition leads off one by one, each would kill the engine except No. 2 cylinder. Taking No 2 off makes no discernable difference. However there is plenty of spark at No 2 - it will easily jump a 15mm gap. The engine smooths out when revved over about 2500 rpm. A couple of blips on the throttle seems to clear it but when allowed to idle, it gets rough again after a few seconds.

On the way home, it seemed to smooth out once up to speed and wasn't running too bad when I arrived. By the time I opened the gate and backed it down the driveway to park it, the rough running returned.

I've started it each morning since then and it always starts up smooth, so the problem only seems to occur when hot. I'm going to try temporarily disabling the EGR valve to eliminate that as a possible cause. I might have to buy another distributor and try that but otherwise I'm stumped. By the way, I've already swapped the distributor cap and leads. The plugs are also new. We did a compression test before replacing the head gasket. No. 2 cylinder was 145 psi and the others 155 psi. I might borrow the compression tester and do the test again but the valves all looked ok when I had the head off.

i would check the plugs again as they may have fouled up with the flooding..

i would check the plugs again as they may have fouled up with the flooding..

Good suggestion, thanks. I will go and do that now. However I think they can't be too bad or it wouldn't run smoothly when cold.

I found a few carbon granules in the accelerator pump inlet and outlet passages. I was previously unaware of those passages, so hadn't cleaned them before.

Could well still be some somewhere getting shaken out occasionally from somewhere and causing problems again.
Check the compression when it is running rough and see if there is any difference on what you had before.
Seems very much like my car had that i posted on before in the thread. Exactly same symptoms it sounds.

Well, it was the EGR (exhaust gas recirculation) valve, so anyone with a carby 1st gen experiencing internittent rough running and poor idle when hot might find it worthwhile to check the EGR valve.

My intermittent rough running problem seems to be EGR related. Although I checked the EGR and the VRV and the thermal valve seems to close off to atmosphere at the correct temperature and all test passed according to the book, I feel that the EGR doesnt shut off during the normal ins and outs of normal driving. I'm reluctant to spend cash on a new EGR valve. I find that when driving normally and when the engine starts to run rough, I just accelerate the revs to clear the roughness and then she settles down. It also appears that when the engine really warms up, there is no roughness in running. I am hoping that continued running of the car will ultimately clear out any crud from inside the EGR.

Rumpfy, check your private messages as I sent a pm re the EGR valve issue. You are optimistic expecting the problem to clear. I think it is more likely to get worse.

Anyhow, having dealt with my EGR valve, I still had a rough idle when hot. The problem was much reduced but still annoying. Having read your post about the carby secondary and air pre-heat diaphragms, I doubt you will have the following issue but will describe it for the benefit of others.

There are two vacuum operated systems in carby model air cleaners that vary with temperature and can affect the idle.

The first is an air pre-heat or H.I.A. (heated intake air) system. A flap in the air cleaner intake is raised by a vacuum diaphragm when the engine is started cold, directing warm air into the intake from a "stove" around the exhaust manifold. As temperature in the air cleaner increases, a temperature sensor reduces vacuum to the diaphragm. Spring pressure causes the flap to lower, decreasing the flow of hot air and increasing cool air flow. Eventually the flap is fully closed and only cool outside air enters the intake. If the diaphragm deteriorates and is unable to hold vacuum, the spring ensures the flap should default to the "cold air" position. The system only operates for a short time after start-up and is barely necessary in australian climate. That's a good thing because 1st gens are now so old that the diaphragm is unlikely to be ok unless it has been replaced.

The second system is a hot idle compensator, a temperature sensor in the form of a bi-metallic strip. When cold, a pad on the end of the strip seals off the vacuum line. As temperature inside the air cleaner increases, the strip bends upwards, lifting the pad away from the vacuum line. This bleeds off vacuum, allowing more air into the intake manifold and leaning the mixture at hot idle. It is a minor thing but has a noticeable effect on the smoothness of the idle.

The important thing to note is that both systems operate by means of a single vacuum line from the intake manifold. A plastic T joint underneath the air cleaner separates the vacuum line into two and routes it to both devices. However, if either device has a vacuum leak, the other will also lose vacuum and will not operate. In my case, the air pre-heat diaphragm was perished so vacuum was lost and neither device operated.

Eventually I will repair or replace the diaphragm but for now I have just by-passed the T joint and fed the single vacuum line to the hot idle compensator, so at least that device is now working properly. It has made a big difference,

Coldy,
did u get my PM.

Coldy,
did u get my PM.
Not the first one - must have gone into the ether. I replied to the 2nd one.

Erratic running of the old girl continues.
I have made up a plate to block the EGR valve.
I tested the EGR valve off the car with compressed air and it did leak. I think it should not leak at all when shut.
nevertheless, I find the car starts and idles very very well, so I dont think there is a air leak into the manifold. The cooling system doesnt seem to be leaking water either.
I have shorted the VSV valve with a wire loop so the fuel cutoff solenoid is always on.
At low engine speeds up to say 2000 rpm, and when cold, the car runs smooth and sweet. When hot, and when travelling at say 90 km/hr, there is a slight hesitations in the engine, but when the accelerator is backed off slightly, the hesitation gets worse, and conversely, when I accelerate again, the hesitation disappears.
the last tank of fuel returned only 18 L/100km; that is I only travelled 370 k on a tank full.
Is it possible that I have the wrong jets in the carby. I did remove the main jets a while ago and I may have swapped them around by mistake.
One jet is about 0.05 inch diameter; the other is 0.09 inch diameter.
Can anyone out there comment please.
I think the small jet supplies the main carby system and the larger one supplies the secondary system. Is this correct.
Prior to all my problems previously, the old girl was giving consistently around 122.5 L/11 K.
Is it possible that the hesitation I feel on backing off the accelerator is due to the mixture becoming far too rich for the engine running conditions at that instant.
I can take the carby off AGAIN, but b4 I do I'll wait for some replies.
thanks guys,
rumpfy.

Rumpfy,

I can't help with your specific questions like the carby jets -- that is too advanced for me. However I'd suggest that if you don't have a factory workshop manual (and I mean from Mitsubishi, not Haynes or Gregorys), you might find it helpful to download the 2nd gen. workshop manual from here: http://depositfiles.com/files/cen9su9k9 (courtesy of member: karj). No-one has scanned and uploaded a 1st gen. manual yet but the TR/TS carby and ancillary components are very similar to the TP. There are some minor differences but I found the manual very helpful. It does describe the location and purpose of the various jets and there is a list of jet sizes in the carby specs (chapter 13).

Be careful what and where you click on that site to get the download. Don't click the green "start download" button. That's a registry cleaner, probably loaded with malware. Click the "regular download" button just below the two circular red dials. Then wait on the next screen while it counts down a delay, answer the text question and if successful, click the grey continue button. The file size is approx. 44 megabytes.

What was the reason for hard-wiring the fuel cut-off solenoid? Was it just to eliminate it as a possible cause? If so, I'd change it back. The cut-off solenoid, apart from its other purposes, is supposed to cut off fuel supply to the carby on a trailing throttle (such as when decelerating or when coasting downhill) to avoid ingestion of excessive quantities of raw fuel.

I doubt that is the cause of all your fuel consumption problems though. In my case it was the float, needle and seat.

Incidentally, although my TP is now running well most of the time, I still have random instances of rough idling when hot. The fuel consumption also varies considerably though way better than it was before.

Thanks coldy.
I hard wired the FCS(fuel cut solenoid) cos the microswitch unit in the vacuum switch had dodgy/dirty contacts which would cause the FCS to operate intermittently if the engine speed was above 2000 rpm. I think that this is now proven to be not the cause of the intermittent running at speeds above 2000 rpm. It was a point to be checked though, because above 2000 rpm the FCS has its current supplied ONLY by the Vacuum switch contacts. Below 2000 rpm the ESS can supply current to the FCS. When easing off the accelerator, the manifold vacuum rises and I had thought that if the contacts were dodgy, the vacuum switch might be operating intermittently and thus switching off the FCS when the vacuum level got near to the normal switching point of around 33 kPa.
The fuel mixture needs to be checked and I wondered if the jets weren’t mixed up by me.
But I had another thought that possibly the accelerator pump ball etc may have fallen out when I dismantled the carby. I think you had a probem like this coldy. I have some details of the carby and will check but maybe you can tell me a thing or two coldy.
I’m wondering if the hesitation when I back off the accelerator isn’t due to the mixture richness being too much at those running conditions; and then when I accelerate, the hesitation disappears because the engine is under power.

Thanks coldy.
I hard wired the FCS(fuel cut solenoid) cos the microswitch unit in the vacuum switch had dodgy/dirty contacts................
The fuel mixture needs to be checked and I wondered if the jets weren’t mixed up by me.
I could be quite wrong because I didn't mess with the jets but I'd be surprised if they can be mixed up. Everything else that I encountered was designed to only fit in the correct place.


But I had another thought that possibly the accelerator pump ball etc may have fallen out when I dismantled the carby. I think you had a probem like this coldy.
Yes, I thought I had lost them but found that it is unlikely unless you remove and replace the gasket between the top and bottom carby halves. I had previously always re-used that gasket and left it stuck to the bottom half. The gasket prevents the check balls and weight from falling out. See posts #12 and #16 of this thread for details.



I have some details of the carby and will check but maybe you can tell me a thing or two coldy.
I’m wondering if the hesitation when I back off the accelerator isn’t due to the mixture richness being too much at those running conditions; and then when I accelerate, the hesitation disappears because the engine is under power.
I agree that could be the case and note that you fully understand the purpose and operation of the fuel cut solenoid. I still think you should re-instate full operation of the FCS even if it requires buying another vacuum switch from a wrecker. I'd explore that avenue first before disassembling the carby again. I've had the carby off mine so many times that I can remove and replace it in a few minutes now but it is still not something I like to do. There's always a risk of breaking or losing something or creating an air leak at the carby/manifold joint.

goodo Coldy,
the jets can be mixed up cos the bible says so.
I think the problem may be the accelerator pump balls. I use a lot of ball bearing balls for my fiddling with the vacuum systems on pianolas and recently I noticed a ball on he floor nearmy work bench and wondered how it got there. i picked the ball up and put it in the jar where I keep these things.
I took the jets out to clean them when I first dismantled the carby; The manual says to identify them and not mix them up. the manual also says to take off the top cover and then turn the body over and catch the ball and weight. i read the words but forgot about that detail.
Just looked at posts 12,16. good stuff. will dismantle the carby now and see whats what.
I'll get back to you about the vacuum switch Dont disagree with what u say. Diagnosis of faults can be a painful, and painstaking, process. Its what we do to understand and then correct the problems. Just imagine how much all this fiddling would cost if we had to pay for it. In my case the old girl gets neglected until its so bad I have to act, and then theres more than one problem to fix and all interrelated.
rumpfy.

quick easy fix EFI it no more carby problemsa

Thanks magnaman.
When the other half bought the car off her girlfriend some 10 years ago, I said I wouldnt have bought it unless it was a efi model. Oh well!!!
But, to refit EFI instead of carby just swaps problems; electronic stuff. and then there's the loom.

Today have checked the accelerator pump balls; ALL OK
Also checked the jet positions; ALL OK.

So I'm totally stuffed now.

Got NO IDEA what to do next. Might fiddle with spark plugs or see if I can land another carby.
But frankly getting a bit disinterested with the failure to even be able to diagnose the problem.
There's GOT to be a reason why it uses too much fuel.
Just keep the thing for a farm car and get something more modern.
thanks everyone for your comments.
rumpfy

i have everthing but a fuel pump here if you decide to efi it . ie loom x5 inlet x8 dizies many coils heaps ex manifolds would even have fuel line,s sedan/ wagon . gen1s are worth the effort .what problems do the efi have ????

Might be making a bit of progress.
I have determined that the air filter is related to the problem of intermittent running in the speed range 2500 to 4000 rpm.
I have noted frequently over the past few months, that the air cleaner element makes a significant difference to the smoothness of running. I did replace the element in february, but when I get this erratic running I find by removing the element makes the engine run smoothly pretty much across the whole engine speed range. Finally last week, I found the element was causing seriously erratic running when revving the engine with the car out of gear. Removing the element cleared this.
I dont believe the element is the cause of the problem, but makes the mixture that much richer and the engine then shows erratic running.
I have checked the spark timing OK. I have checked the carby settings with vacuum gauge OK.
What I am wondering is if there is some problem with the carby to manifold gasket. I make my own gaskets cos they are quite a simple shape; but I'm wondering if I might be missing something and perhaps blocking some port or other. Does anyone have a scan of the gasket that I can check the cut outs.
The car is consistently returning 16 L per 100 Km. I am sure it has nothing to do with fuel level in the bowl.
Anyone got any comments/experience.

Get some aerostart and a probe for the can and spray it around the gasket areas with motor running if it is sucking air you will soon know.
Problem is normally you get a lean condition if the gaskets are not sealing.
Also check the choke butterfly maybe it is loose and moving sometimes causing the rich condition.
Air filter element would have to be reasonably clogged to make the engine run rich and the small amount of restriction caused by a new filter would not be enough to tip the mixture over the edge and cause rich running.. Could also be a restriction in the air filter housing doing it so check the warm air system or it is malfunctioning as warm air will cause a richer mixture as the air is less dense........Also double check the air injection system for faults. As for gaskets might be best to just buy them i have a few but will not be home for months to scan them. Vee

Thanks Vee. I have a vacuum gauge and used it in conjunction with the diagrams given in the Mitsubishi manual. ALL vacuumeadings and behaviour were AOK. The idling performance is really good; no fits and farts at idle and thgere is NO leakage at the inlet manifold.
I agree that it seems unbelievable that the air cleaner element can tip the thing over the edge; BUT it is happening. I have checked the air cleaner and the ducts and everything is clear. I have not looked into the space under the mudguard where the air inlet actually comes from, but i have shoved the garden hose down there to clear anything that might be there but always there is the option to remove the snorkel duct from the entry to the air cleaner housing.
i think your advice about shelling out for a new gasket makes a lot of sense. Your comment about the warm air system is OK and the thermostat had been incorrectly set AND was causing BIG problems. That is now sorted and the warm air system and the vacuum motor are OK. The choke is OK; opens when hot and doesnt flop around at all. After I fixed the warm air system the engine was running rough at between 2500 and 300 rpm and removing the air cleaner element fixed the problem. After using half a tank of fuel, the fuel consumption is still around 400 Km per 65 or so litre. I am not using an air filter element currently so there is still this problem of high fuel consumption.
I will get a new carby/manifold gasket and check the car again.
I find that many of the 'above the throttle' ports connect to the carby throat through channels cast between thet gasket and the carby body and I wonder if, at these places, the gasket should be cut to allow a greater area for the flow of gasses.
pr.

What colour are your sparkplugs burning?? They should be a whitish grey colour which is normal.
If it is rich they should be blackened.. Brilliant white and too lean.
Between 100/110 steady with aircon on and i have an auto i regularly get 9.5 litres per 100km with overdrive engaged approx 2500rpm.
Driving style is a big thing with these 2.6 Magnas.
Also may pay to check your handbrake is not dragging a bit or the other brakes.
I have a spare carby i could sell but will not be home for several months.Vee

Ps is your thermostat ok and does the motor get to normal operating temperature??

16L/100 km is about 18 miles per gallon, sure is a lot of fuel!
Then again, the 2.6L Sigma GJ auto used to run at about that, around town with lots of cold starts and short trips, anyway.

Probably worth backing off the choke adjustment so that it still starts and doesn't stall when cold, but comes off quicker. The mechanism gets real lazy as it ages and causes rich running when warming up in the rev range you mention. I vaguely remember a conversion to manual choke was a possible mod to do on the Sigmas and carby Magnas.

I found fuel consumption just got better going to a TP EFI 2.6 manual, then TS 2.6L EFI manual, and currently 3.5L EFI TJ auto. Benefits of EFI and more accurate tuning of the fuel/air ratios, I guess.

Benefits of EFI and more accurate tuning of the fuel/air ratios, I guess.

Thats it pretty much. Carby supplies all cylinders and you often get mixture differences in each cylinder where injection gets it exactly right for each cylinder.Better mixture response on warm up where chokes can be slow and lazy and often don't completely open up causing rich running at all speeds!!

How much difference in fuel economy between TP auto/manual on the highway?? Then what does a TS manual get? All 2.6 of course.
I note the Ts only has about 8kw more power (regular ULP) than a TP......... but TS is a heavier car so a TP with TS injection should be way better i would think as i'm sure the TS ECU and the uprated fuel rail pressure & different injectors will make a big difference to a TP Vee.

When they are running well, there isn't much fuel mileage difference between carby and efi TPs. There is a huge difference between city (stop-start) and country cruising though. They are both dreadful in the city.

For country driving, I have never been able to get as good a mileage out of my efi wagon as the carby sedan. I put that down to the greater weight and drag of the wagon body. The efi was more consistent though and in recent months my carby sedan has been as thirsty as Rumpfy's. It is a lot better now and getting around 10 litres per 100 km but I'm still having random bouts of rough running. I will start another post about that.

Rumpfy, the manifold to carby gasket in mine was original and was a metal pressing. When I put the new bits in the carby, I used the cardboard gasket from the carby rebuild kit, so I still have the original. Here is a scan of it:
http://users.tpg.com.au/acheson1/images/GASK1.JPG

This is it converted to a silhouette:
http://users.tpg.com.au/acheson1/images/GASK2.JPG

Whoa! I didn't realise they would come out that big. Hopefully you'll have some image editing software to scale them down to size. To help in that regard, the four bolt-holes are 8mm diameter and they are on 80mm centres horizontally and 44mm centres vertically. Alternatively, the distances between the inside edges of the holes are 72mm horizontally and 36mm vertically (or from the outside edges, 88mm and 52mm).