warm running

[norsenoddy]

HI I have an 86 1.9 dg motor which has never failed to start ( except when the battery died )runs well when started from cold , but I often drive about 5 miles and stop for 1/2 to 3/4 of a hour , start it again no problem but it stutters and surges with no power unless you give it lots of revs .Plugs have been replaced ( it did feel like when a plug breaks down under load ) but no change , all leads and distributor cap renewed . as I say if you start from cold and keep driving no problems , I'm really suspecting the choke but not sure how to test this theory ? any help gratefully received

[ghost123uk]

I'm really suspecting the choke but not sure how to test this theory ? any help gratefully received

That is quite easy, 2 ways to check it =

1 = take off the air filter housing and look into the carb when engine cold, you should see the choke flaps at the top of the carbs air intakes and they should be closed. Then do the same when warmed up and they should be open.

2 = Temporarily, use a bit of wire on the external linkage to the choke flaps to wire them stuck open and test drive it (might take a bit longer to start from cold like this. obviously )

I often drive about 5 miles and stop for 1/2 to 3/4 of a hour , start it again no problem but it stutters and surges [and] as I say if you start from cold and keep driving no problems ,

That is odd. If it misbehaved as it got warm and did it all the time it would point to the coil or the hall sensor in the dizzy or the ignition amp (black fag box sized thing at the front left bulkhead in the engine bay).

All of the above 3 things are easy to change, 1 at a time (borrowing them off another T25 ?) until the problem goes away. But, yours only misbehaving after a short stop is a puzzle. Others will be along with more ideas soon

[norsenoddy]

cheers I'll start testing see if that shows anything