Weber 32ICS

[fv102]

I have a Weber 32ICS on a Swiss series 1.
Currently encountering a problem where the carb is filling the choke tube with fuel even when the engine is turned off and just the pump running. When the pump is stopped ie the key is pulled this process appears to continue on residual pressure.

Just wondering if anybody has encountered this issue before or has any knowledge of the Weber 32 carburretor before I pull it?

thanks
Darren

[AustHaflinger]

Hi Darren and a warm welcome to the forum - can you tell us where you are - put it in your profile.

From your comments "when the engine is turned off and just the pump running" I take it that you no longer have the mechanical fuel pump and have a fitted an electric pump. If so is its pressure too high. You only need about 2-3psi.

Garry

[fv102]

Hi Gary,

Swiss Series 1, in my care it has always had Hardi electric pump which has been in excess of ten years.

I've had a further look at the books this morning and I'm slowly coming to the conclusion that the float needle valve is struggling to hold back any residual pressure in the pump line, pushing it in the choke tube, however it does seem a significant amount.

This all kicked off when I started looking for a poor transfer problem from slow running to main jet.

Darren

[AustHaflinger]

Hi Darren and thanks for updating your location - John (heinkeljb) who is not too far from you should be along before too long to say hello.

I am not all that familiar with earlier Hafs and just assumed it had the later mechanical fuel pump - though I have an aftermarket electric pump on mine.

The problem you describe certainly does sound float related - if you have been running the fuel pump for a long time then not likely to be excess fuel pressure. There could be dirt/varnish in the float needle stopping it closing when the chamber is full. Likewise float level settings should be Ok based on previous running - however if you have a floats that have varnish build up so are heavier than they should be could cause the valve to stay open (unlikely though).

The obvious one is that the float has developed a pin hole so is half full of fuel so has sunk in the chamber or is floating low with the weight.

I think you need to gain access to the float/s (not familiar with the weber) and check them out and check the float needle valve to ensure all is working as it should.

Cheers

Garry

[fv102]

Hi Garry,

After a fresh nights sleep and refreshing myself of the circuits in this quite basic carburretor it become obvious that the residual pressure when the electric pump was switched off was pushing fuel past the needle valve and through the carb onto the throttle butterfly. Easy deduction from there, it could only be the float or valve or as it turned out to be a bit of both!

The needle valve had a ridge where it meets the entrance oriface of the valve, I've been succesful in removing this ridge and it will suffice until a new one arrives.

And the float was part full of fuel, both sides but more so on one, obviously just sufficient to reduce the upward effort on the needle valve. Once the petrol was removed and they were dried out the the carb was re-assembled and I took it for a run, so far all appears well. Oh and the float settings were way out, never had a reason to check them before!

Darren

[AustHaflinger]

Great minds think alike

However there was a reason the float had a bit of fuel in it - a pin hole. Without replacement or sealing it will fill again and you will have problems again.

Replace the float needle as you intend and also replace the floats or repair them.

Good luck

Garry

[heinkeljb]

Welcome Daren,

I am currently on holiday in crete for a week so haven’t really been bothering with Internet things! Anyway, I would have said the same things as Gary, in that encases fuel is usually down to three things.

Electric pumps that supply too much pressure.
Needle valves that are damaged.
Floats that are damaged.

Looks like you have found the culprit(s) and absolution in hand.

Well done.

John

[AustHaflinger]

I am currently on holiday in crete for a week so haven’t really been bothering with Internet things!

Its good for some - dont get too much sun

[Julian B]

I have a similar carb in my 1962 "pre" Series Haflinger over 10 years ago; on a run out in the Italian countryside near Hafling village it conked out & died. Very embarrassing. Turned out there was a pin hole in the float and it had sunk. Thankfully someone was there with a NOS replacement and its worked perfectly ever since.

[mechanical horse]

Hey all,
A word of warning.When you find the hole or crack in the float drill a small hole in it so that yo can shake rattle and role the thing and get the fuel out of it.When it is empty and dried out you can just solder up the hole and the problem is solved.
When I was a brand new apprentice I was doing this job on a carby and was in a hurry and instead of shaking the fuel out of the float I decided to put a match to it and hurry the process along. All went well until the fuel/air mixture was just right for a small explosion. It went off like a Hong Kong cracker and opened up the float so much that I could have put my finger in the hole.
It gave me a bit of a startle to say the least, but it frightened 10 years of growth out of the Foreman who happened to be standing behind me.He gave me a very detailed lecture on the "Theory of Combustion" and also where his boot was going to be planted if I even thought about doing it again.
Regards Rick.

[AustHaflinger]

The other aspect is that adding solder to an area that originally did not have it can make the float heavier so it then floars lower in the petrol so changing the petrol level in the float chamber - can normally be corrected by resetting the float valve adjustment to compensate.

Garry

[heinkeljb]

If the float has a crack in it, get the smallest drill you can and drill a hole at each end of the crack. Clean well with the finest emery cloth you can get, wipe a layer of flux over the area, heat with a blow torch or as big a soldering iron as you can get. Easy way is to get a length of copper earth wire, fold it on itself and hammer it tighter to make. Lump with a small length to use as the soldering point. Heat the lump with a blowtorch and the float, apply a layer of solder - make sure you seal all of the crack.

Now use the emery cloth to sand down the solider to the thinnest layer you can that still seals the crack.

As Gary says, you might have to adjust the “U” shaped arm that holds the float needle valve to get the float level correct again, but it should not be by much.

Good luck

John

[fv102]

Gents,

Thanks for your help and interest, it hasn't escaped me that the petrol has found it's way in to the float and it could possibly happen again despite a careful scrutiny of both halfs. Yes the errant fuel was removed through a small drilled hole that was soldered back over, the solder is such a small amount that I doubt it has such a significant effect.

The truck appears to be running much better now and there is no longer a pool of fuel building up in the bottom of the carb every time the motor is stopped. I suspect the poor needle valve has been dripping into the carb in this way for quite some time and on reflection has been evident everytime the motor is re-started although this can very easily be missed on an old boxer engine.

Darren