Carb Problem? Overfuel, Common Reasons?
Turbo Mini Forums

Ive tried the search but couldnt find anything relating to what happened with me.

Right ill start by explaining the situation.

My engine has been stood for 3 weeks (not run) in a garage (which gets cold) i took all the carb/plenum/inlet off as one big piece and left it covered up on the workbench.

Now, ive put my new t2 turbo on and put the carb back on with new ex manifold gasket, all plumbed in correctly etc.

Started her up and she was running as she normally would, Bit lean then to normal afr of 14.5-15 at idle. Once it was warm i gave it a bit of a rev (approx 4,000rpm) about 3 times. then i left it to idle, then literally 3 seconds later, i could hear it bogging down then it cut out after 5 seconds. while this was going on i noticed the afr was 11.2 soo its overfueling.

Tried to restart the car but with no joy at all, took the plugs out and theyre wet. so its flooded.

My question is, could this be choke related? bear in mind i never ever use the choke. There is oil in the dashpot.

Since this, ive left the plugs out and taken the dashpot off and there is puddles of fuel in the carb intake. Also if i was to pull the choke leaver would this make the jet move? (the one you see when you take off the dashpot?)

Sorry for the long winded explanation, i try to explain things clearly.

Any help is appreciated

Thank you, Johnny.

More likely needle valve not seating correctly.

Why wouldnt you use the choke for cold starting ? That's why its there.

And no, the choke does not make the jet move in a HIF style carb

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

is the needle valve that little thing in the base of the carb? im assuming it could have got some crud fuel in there since its been sat for 3 weeks?

Ive never used a choke, i always leave the car to warm up before driving, never need the choke either.

Right no problem, never really messed with a HIF style carb.

Needle valve is inside the float chamber and is what controls fuel flow into the chamber from outside ( ie the rubber pipe )

I see no reason why sitting anywhere for 3 weeks should pose a problem. But anything can happen.

you could try taking the dashpot off and watching the jet as you enable the fuel pump.
If fuel is coming out, the needle valve is not sealing properly for whatever reason

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

yeah, thats the one. I will try that, ive got the dashpot off now anyway, so that the fuel evapourates. Will it come out at speed? Or will it trickle out?

ive turned on the fuel pump with the dashpot off, and theres no fuel coming out. Im going to just put the dashpot back on and try it again. Ive cleaned the plugs and checked all the ignition side of things.

Often fuel soaked plugs are only fit for the bin. But you might get lucky.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

its all good now, problem ended up being the needle valve (i think).

I did try it again with no luck. so i took the dashpot off again only to find loads more fuel. there was a little pool of fuel in the intake (see pic) so i took off the carb, as i was taking it off when i pulled off the blocked up overflow pipe it spewed out fuel (obviously) but so did the plenum pipe too! there was that much fuel. Anyway i dried up all that and emptied the carb took the bottom of the carb off and litterally just took it apart, cleaned with carb/brake cleaner and put back together. now runs as it did before. The spark plugs seem to work fine though, why would fuel soaked plugs be no good?

ALSO, will the heat off my exhaust manifold melt my IC pipework (see pic)

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Certainly a lot closer than I'd be running a boost pipe to something that will glow absolutely red hot lol

No idea why they fail. But the mount of times Ive tried using plugs that have been soaked, even after drying them with a blowtorch. Most of the time they simply refuse to spark.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Well i thought that, but the turbo was bought off here, in working condition... which it is, but ive had to modify a lot of things on it to even get it in a state to put onto my mini, anyway ive done the modding and now it seems fine but i still dont like the fact that its that close! specially if i want to run high boost.

Ive always just given spark plugs a wire brushing and then bit of a rub with wet n dry. always works.

Wont matter what boost, it's still going to get bloody hot !!!!

You'd be better with an aluminium elbow or something welded onto the turbo exit to give clearance before anything meltable or burnable

And cleaning old copper plugs in that fashion is ok. NEVER try and clean a precious metal plug like that or you will destroy it.

As I say though, when you do have issues and plugs have been soaked. Easiest thing is to bin them for new ones. At least you know the plugs wont be the cause of non-starting.

Edited by stevieturbo on 24th Jan, 2011.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

yeah i have a feeling its going to melt. i think its rated at 200c hmmmmm well if it does melt, what is the worst that can happen? besides a bit of smouldering. if it does infact melt and burn a hole the turbo will blow it out and leak air? if this happens i will have to take it all off again and get a piece welded on.

I dont want to sound like im trying to do the bodge solution, ive just been having such a nightmare getting it all to fit and now that its all on i dont want to spend another 4 weeks taking it all off and putting back on. plus the garage i had it in is no longer available :(

just as an extra measure, i put some heat resistant mat around the pipe, hopefully this should help.