6 replies to this topic

[runkthepunk]

1275cc A+ Metro Carb with Stage 1 Kit HS4 Carb (soon to be HIF44)

Okay I have been having trouble for a while but now my major concern is:

when the car has been driven for a while and the engine is nice and warm if I stop to fuel up or whatever its really difficult to start the car again, I have to give it loads of throttle and it roars back to life but then splutters for a while until back on the road and driving for a bit.

Its annoying because it used to be fine when warm but now it starts like a Donkey! In fact it starts easier from cold!

I have been told about something to do with gases building up that need to be expelled what does this mean?

thanks

Rob

[Pauly]

Might be running lean, fuel evaporation due to the heat?

Paul.

[runkthepunk]

Thanks for that,

Okay its strange though because it only developed this problem after tuning.

I was told that perhaps because the heat coming from the (stage 1) exhaust 3-1 manifold is more than the standard unit that is causing a gases build up?

I guess its not that bad a problem but whenever I try and start it from warm it really struggles

any other ideas?

Rob

[Ibexx]

Sounds like 'vapor lock'. Should be solved with a new fuel pump or better: an electric fuel pump.

http://www.wisegeek....-vapor-lock.htm

[runkthepunk]

I think it is indeed vapour lock,

my new question is: what is best to use to fabricate some kind of heat shield?

Has anyone else had this problem? or has anyone else fabricated a heat shield to stop this sort of thing happening?

I presume I should use stainless steel and I am also going to run a flexi-pipe from the grill up to the underside of the carb to help keep air circulating/keep it cool. I'm not sure where to attach the heat shield but maybe on the rest of the studs on the manifold if there's enough space unless anyone else has any ideas?

Rob

[lrostoke]

With it being an HS4 it could have the waxstat jet fitted.. the whole point of this jet is to weaken the mixture when everything is nicely warmed up.

Its possible your waxstat is playing up, or your mixture is a bit on the lean side, and when the waxstat kicks in it becomes weaker still

[runkthepunk]

With it being an HS4 it could have the waxstat jet fitted.. the whole point of this jet is to weaken the mixture when everything is nicely warmed up.

Its possible your waxstat is playing up, or your mixture is a bit on the lean side, and when the waxstat kicks in it becomes weaker still

I don't know if its waxstat or not they both look pretty similar to me, the mixture is abut right as its been colour tuned and looks bob on. The carb is going to be replaced with a HIF44 but I think by making a heat shield that can stay in situ I can avoid this sort of problem in the future.

I do agree there is something wrong with the carb its knackered really, but I am surprised as the heat generated by the stage 1 kit must be something everyone has to deal with but no one else seems to have mentioned any problems dodgy carb or not but surely i can't be the only one?

I will buy some bits and bobs tomorrow and see what happens