Guys, my TM has an intermittent fault where it occasionally likes to rev and stay at around 3000RPM. There doesn't seem to be any rhyme or reason as to when it happens. The only way I can get it back to normal is to turn the car off and it will run on ( and keep running!) and drop the clutch. Then when I start it again, most of the time it is idling normally. The throttle cable seems to be free and moving ok. Any ideas what might be wrong?

Thanks
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I should have added that it is a carby model which was rebuilt about 4 years ago.

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check all vacume lines
dashpots

it maybe like the secondary butterfly is sticking
or the choke

running on after it is switched off sometimes called deseling
is usually a timing problem or carby running too rich

Thanks mb. How can I test to see if it is running too rich?

if there is black smoke or an unburnt fuel smell
out the tail pipe

the expensive way is a dyno tune approx $300(a guess)

Thanks mb. I might have a play around over the weekend.

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