eek solex carb fuel leak

honolulujoe · Jul 6, 2014

I noticed this morning - and I think its been doing it for a while - when the ignition is turned on fuel leaks out of the carb, seems to be from the throttle mechanism, from the threaded bit with the nut on it which connects to the lever at the bottom which is part of the throttle.

is this an easy fix or is it a new carb job

once the engine is running the leak stops

blue beasty · Jul 6, 2014

Don't know if it's common or how much of a pain it is to sort but you can get refurb kits for them off fleabay

honolulujoe · Jul 6, 2014

thx I will check it out.

Problem doesn't appear to be as simple as I thought, it only seems to do it when I get back from a trip when everything is hot, the nut itself seems pretty tight

blue beasty · Jul 6, 2014

honolulujoe said:
thx I will check it out.

Problem doesn't appear to be as simple as I thought, it only seems to do it when I get back from a trip when everything is hot, the nut itself seems pretty tight

Probably the spindles worn, I know Zeniths suffer from that. Whip it apart and have a look......what could possibly go wrong?

Here's a pretty picture

honolulujoe · Jul 6, 2014

dread to think what could go wrong

dominicbeesley · Jul 6, 2014

It looks like it is probably coming out around the throttle spindle (item 36 on diagram). They are not a gas-tight item so can weep. Usually they leak the other way (drawing in air rather than ****ing out fuel mixture). However on the over-run or if backfiring you can get some back pressure that actually pushes the fuel out.

If the spindle is very loose a replacement may help but you'd probably find the carb body is a bit worn too.

It doesn't look like a lot of fuel, I'd not worry about it unless there is enough to fill the bonnet up with vapour i.e. it REALLY stinks of petrol. Even my brand new genuine weber gets a bit of wetness around the spindle occasionally...

Have a feel around though, if its coming from higher up then a rebuild might be in order.

honolulujoe · Jul 6, 2014

thx, I am pretty sure it is the spindle, so maybe I will keep an eye on it and try to understand better when it happens, maybe get a kit in ready, it doesn't stink anything like it did when the fuel pipe went last month.

that diagram blue beasty put up is becoming less daunting the more I look at it

if all else fails and i make a pigs ear of it, there is a chap in the s1 club that is advertising to fully refurb your carb for £165 including parts

honolulujoe · Jul 9, 2014

just occurred to me, when I replaced the fuel pipe I used a piece that was almost twice as long as the previous bit, could it be that there is now too much fuel between the pump and the carb so that when you turn the ignition on after you have recently been out and the pump primes up doing that ticking thing it does this excess fuel takes an easy exit via the spindle.

dominicbeesley · Jul 9, 2014

In a word "no" - the length of the pipe should make no difference.

The way it works is that the pump keeps pushing fuel all the time, there is a valve attached to a float in the carb which only lets fuel in when it is below a certain level.

If that valve is badly worn or badly set up or the wrong pump is fitted (which makes too much pressure) then it can overflow but it would do it before the engine was started with just the fuel pump running and I thought you'd said that this only happened when the engine had been run.

Maybe, if you recently replaced the pipe the writhing that you have to do to push it on / pull the old one off has torn a gasket....more likely if it doesn't really stink is that its always done it and you've not noticed!

honolulujoe · Jul 9, 2014

drat

thanks for the explanation.

well that's my thinking done for the week anyway.

Yes it does only do it after a trip if I leave the ignition on.

when I turn on from cold the pump does its ticking for a few seconds but nothing leaks
from the carb.

think I will get a kit and over haul the carb sometime during the winter when I don't use the s1 much because of the lack of creature comforts and decent heater/demister.

I bet the carb is original and wasn't changed/overhauled when a po put the recon engine in

eek solex carb fuel leak

honolulujoe

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blue beasty

Leaks an prone to bits dropping off

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blue beasty

Leaks an prone to bits dropping off

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