could anybody tell me wot causes running on after engine is

[jasonp62000tc1972]

hi all firstlly thanks for the worm welcome since joining this forum iv got a p6 2000tc it runns on for ages after the engine is switched off can anybody tell me wot causes this also i think the carbs need sorting out setting up etc would this cause the running on also is there a pub meet in the south or near southampton thanks jason

[TokyoP6B]

Quite possibly needs a decarb, hot spots in carbon buildup under the cylinder head will do this; there may be a product that you can pour into the petrol while the engine is running and hot that might save taking the cylinder head off I recall using one called "Redex" on one of my old English 4-cylinder cars that ( temporarily ) produced clouds of smoke out the exhaust and stopped exactly this problem tho' a more permanent fix will involve taking the cylinder head off, scraping carbon off the piston tops + lapping in the valves + then resetting the clearances

GW

[KiwiRover]

Or maybe just a good tune up. The TCs are quite prone to this and everything needs to be spot-on to avoid it. Make sure the carbs are balanced properly and the mixtures are right (not too lean, they don't like it.) Check for vacuum leaks and play with the timing a bit. You also need to be using the highest octane fuel you can find. They were designed to run on 100 octane and aren't entirely happy on anything less. Mine used to run on and pink when all I could get was 95 octane. Simply switching to 98 when it became available fixed all the problems.

[jasonp62000tc1972]

Or maybe just a good tune up. The TCs are quite prone to this and everything needs to be spot-on to avoid it. Make sure the carbs are balanced properly and the mixtures are right (not too lean, they don't like it.) Check for vacuum leaks and play with the timing a bit. You also need to be using the highest octane fuel you can find. They were designed to run on 100 octane and aren't entirely happy on anything less. Mine used to run on and pink when all I could get was 95 octane. Simply switching to 98 when it became available fixed all the problems.

thanks for your reply i might take the head off but ill get her tuned up first iv got a gasket set so this will be last option although its done 58000 miles and its only done 2000 miles a yr so a build up of carbon is proberly the problem also the plugs are black so as u said carbs need sorting aswell

[DaveHerns]

It could be that the tickover speed is too high

[keanej]

Check what plugs you have in the wrong ones can get hot enough to ignite the fuel without a spark whuch can cause the running on

[roll]

Hi. Had same problem with my 2000 TC after its engine rebuild. Sent it back to rebuilder (highly recommended chap called Kerry Lindsay in Wellington NZ) and he diagnosed problem as idling speed being too high. The cure was to set speed at 800 rpm. Hope this helps.