Fuel Leak

Post by **fweddy** » Sun Feb 15, 2004 7:39 pm

The author of 'Water Leak' returns with the next question in this series...

Perhaps its a fuel gush rather than a leak. I haven't tried really investigating yet and I thought I'd put it to you here for a quick reference.

When I go to start the vehicle the fuel pump starts clicking to pump the fuel up. When it pumps up it keeps going and where the hose from the pump joins to the fuel bowl fuel starts gushing out. It's not the hose that's not connected properly but just below the line-in there is a small hole which is hidden by a metal shield - the fuel is coming out here.

I suspect the hole is there as a release or overflow but why is it coming out when the fuel is just being pumped?

Any suggestions before I start investigating further and figuring out how its really ment to work?

Post by **rayofleamington** » Sun Feb 15, 2004 8:06 pm

Sounds like a sticky needle valve. The float is meatn to push the needle up until it closes the filler hole - Sometimes it is a bit lazy, so the fuel keeps flowing into the carb and it overflows exactly as described.
Either:

1) the needle or seat has got some debris on it which stops it operating correctly, or
2) the float is set wrong, or
3) fuel has got inside the float or
4) The needle or seat is damaged

That's the order of probablility based on my nearly non existant experience....

On some cars the needle sticks for just a second, others it sticks when the engine is running (it needs the engine vibrations to free it up), and other times you get a constant leak.

Post by **brixtonmorris** » Sun Feb 15, 2004 9:41 pm

youll need a flat blade screwdriver to undo the three little screws holding the cover on. you will probably need to remove the air filter and filter base plate, as its obstructing one of the screws. try and protect the gasket on the flot chamber, dont take it off, it may still work.when you remove the cover the float comes with it. just carfully clean out the chamber of brown dust, check all is in order with the float. and that it moves. put it all back together, and try your luck with the ingnition key. thats usally all it takes.

Post by **fweddy** » Mon Feb 16, 2004 7:53 am

Thanks both - that sounds exactly along the lines I was thinking - I'll try having a clean out first - It was working the other day with only a slight leak so it seems it might be a bit of muck that's upset it. I'll sort it some time this week.

Post by **Willie** » Mon Feb 16, 2004 4:13 pm

You may be lucky with a foreign body in the needle assembly
but usually,once a leak starts the only answer is to buy a
needle and seat assembly and replace the old one. The only
problem is in undoing the recessed nut, otherwise no problems.

Post by **salty_monk** » Mon Feb 16, 2004 5:19 pm

The author of 'Water Leak' returns with the next question in this series...

What comes next??? Oil Leak

Post by **fweddy** » Mon Feb 16, 2004 7:34 pm

Well we have no evidence of that yet and the oil has been in it for a week or so now but then again it hasn't been running much yet.

We also have potential for further issues

Windscreen-rubber Leak
Diff Oil Leak
Gearbox Oil Leak
Damper Fluid Leak
Brake Fluid Leak
Windscreen-squirter-bottle Leak
Tyre Air Leak
Information Leak

Sorry I don't mean to be a leak freak so to speak

Post by **57traveller** » Tue Feb 17, 2004 9:24 am

To release the recessed hexagon on the needle valve seat assembly I obtained a cheap ring spanner of the correct size and reduced it's thickness by grinding around the outside until it just fitted into the recess.
Although probably not the case on this occasion I had a similar leak once but the fuel pipe had a small split at the hose clip and the fuel was spraying against the carb. bowl bouncing off and confusing the issue.

Post by **salty_monk** » Tue Feb 17, 2004 9:53 am

I've covered a few of these "Leaks" myself in the last few months!!

Post by **Cam** » Tue Feb 17, 2004 2:05 pm

You used to be able to get an SU tool kit with all the spaners etc in the kit. I don't know if they are still available. I was thinking of getting one about 10 years ago but as usual I never got round to it!!

Post by **fweddy** » Thu Feb 19, 2004 7:16 am

57traveller wrote:I had a similar leak once but the fuel pipe had a small split at the hose clip and the fuel was spraying against the carb. bowl bouncing off and confusing the issue.

That was my first suspision and I cut the rough end off the pipe to 'fix' the problem but further investigation showed I only shortened the pipe (and made it look tidyer).

Post by **57traveller** » Thu Feb 19, 2004 10:28 am

Unfortunately that wasn't my first suspicion fweddy, only found on refitting the pipe after dismantling the bowl assembly, cleaning and checking. At least I have a clean bowl, new needle valve and float.

Post by **fweddy** » Sun Feb 22, 2004 8:19 am

This problem is all fixed while the water leaks continues to be problematic.

I took the top off the bowl and gave it a good clean - the main problem was in the bit where the float pushes up on - bit mucky in there and it wasn't going up and down right. Gave it a good clean and it moved better. On putting it on again the gasket was shot - thought I've have to go get another one but checked another carb first and found a good one there - put it all together and its doing its job fine.