1.1 stalling problems

Having problems with my 1093cc stalling. Runs fine from cold and when warmed up, but when stopped (once warmed up) for anything from 5min - 1 hour it will start, but the revs drop almost instantly and the engine stalls.

This can be avoided if the revs are kept up with the throttle or if I pull the choke out a bit to keep the revs up. Also noted that if I try and start and it stalls and and leave it another 5 mins it will start and run fine. The problem dissappears after about 10-15 mins of driving.

I'm at a bit of a loss as to what could cause this sort of problem or where to start :dontknow: . Carb, plugs, HT's, points, condensor and coil have been replaced in last year and the problem only effects the engine when idling. Any help much appreciated.

Cheers

Mark

Try the Fuel Line & the Fuel pump,

Check the points & the rotor arm once again.

Hope this solves it.

Cheers
 8)

Also check the routing of the fuel lines to the carb - if it's poor (too close to hot engine parts), the fuel in them when the hot engine stops gets a blast of heat for a good few mins and vapourises. The fuel pump can't pump vapour (only liquid), so when you re-start, you get very little fuel for a while.

Sounds like it might be the thing, as your engine gets re-started using the (cooler) fuel in the bowl on the carb, but then things go downhill…

Re-route the pipes, or lag them with insulating material to keep the heat away.

Thanks, I haven't had a chance to have a proper look it, ben run off my feet welding my GTI. Am I being simplistic or is fuel vapourisation more pronounced in hotter weather? From memory the fuel pipes do run close to the head, but obviously this is necesasry to route into the pump, might lag them and take it from there.

Cheers

markwon said

Thanks, I haven't had a chance to have a proper look it, ben run off my feet welding my GTI. Am I being simplistic or is fuel vapourisation more pronounced in hotter weather? From memory the fuel pipes do run close to the head, but obviously this is necesasry to route into the pump, might lag them and take it from there.

Cheers

It is more pronounced in hot weather, but can happen any time if the conditions are right. Re-starting after a few minutes can be "the right conditions".

Deep Explanation (in case you are interested):
The engine, which had been getting rid of its heat through the coolant, can't do that any more (water pump stopped with engine), so the heat that has been made just before stopping radiates & conducts out of the engine, into the air in the engine bay and into the components touching it, including the carb and fuel lines) - for a few minutes there is a big heat spike, before the whole lot begins to cool. Unfortunately, you are trying to re-start during this spike. Moving/lagging the fuel pipes will help stop some of the conduction & radiation of heat from the head into the fuel lines.

Thanks for that - always interesting to know why/how these things happen.