11 replies to this topic

[adcyork]

When i ran my engine today fuel was pouring out of the overflow pipe constantly and only stopped when the engine stopped. The only thing i could think was that the float was sticking in the float bowl. I took the top off the float bowl and checked the float was moving freely which it was. I also checked if the float needle moved freely and that is fine too. why else would it overflow?
i need to sort something out very sharpish as i'm using as much fuel in the engine as i'm loosing onto the floor through the overflow!
anyone any ideas?

[Major Burkenshaw]

Is it possible that the float has a hole in it? Don't know if this make it over or under fuel though?

[adcyork]

no the float definetly doesn't have a hole in it and that would cause it to overfuel yes as the float would fill up with fuel and sink in the float bowl meaning it would not shut off the flow.

Edited by adcyork, 07 January 2007 - 12:46 AM.

[cowboy]

as the major says. you probably have a hole in your float in your chamber. which means that as the fuel is drawn into the chamber instead of the float, rissing and pushing the valve up to stop the flow of petrol into the chamber, the fuel just keeps getting into the float chamber.

if you remove the top of the float chamber and lift it out if it has a hole in it you will see fuel in the float.

if that isnt the problem then look at thr valve which is in the top of the housing.

let me know if you want to know more

[adcyork]

cowboy: the float definetly doesn't have a hole in it as i checked when i had it out earlier. As for inspecting the valve assembly, what am i looking for?

[cowboy]

ok you will need to remove the top of the float chamber.

then you will need a thin punch and rmove the float from the top. the valve will then pop out, if this is damaged then it wont do its job

minispares have a few differant parts, you can get the float chamber or just the needle valve

Edited by cowboy, 07 January 2007 - 01:27 AM.

[dklawson]

Replace the needle valve and re-adjust the float level once the new parts are installed.

The standard SU float valves have tips that wear out. There's also the chance that there's something preventing the valve from seating. Regardless, the parts aren't expensive and they're easy to replace.

[MRclubman1100cc]

Hey i had this problem as well and i just got a new seat and needle, also i put a fuel filter on it as it didn't have one in the first place..... i hurd that that if u don't run a fuel filter fine particles get trapt between the needle point which stops it from shuting off and thats sometimes it over flows out the top..... as i said get new seat and needle and if u got have a filter on the line get one...

[miniboo]

just a thought: are you sure you have the pipes connected up right?

[adcyork]

Hey i had this problem as well and i just got a new seat and needle, also i put a fuel filter on it as it didn't have one in the first place..... i hurd that that if u don't run a fuel filter fine particles get trapt between the needle point which stops it from shuting off and thats sometimes it over flows out the top..... as i said get new seat and needle and if u got have a filter on the line get one...

i haven't got a fuel filter so i'm going to put an inline filter on as i think the reason it was overflowing was dirt blocking the jet like you said.

just a thought: are you sure you have the pipes connected up right?

yea i have the pipes on the right way deffo.


The problem has now sorted itself out and there is nothing coming out of the overflow at all so all is well. I'm going to replace the needle and float anyway just to be sure it won't happen again.

thanks for the help lads

[MRclubman1100cc]

Na thats fine thats why were here, to help others out

[Big Man]

Glad I checked SEARCH before asking a question that has had loads of cracking advice

Cheers BM