Weber 32 / 36 carb jets

[Tnick]

Following on from my earlier post I bought a 32/36 DGAV off ebay - cleaned it out and fitted it. No problems in starting, auto choke switched off as it warmed up. However I could not get it to idle and slow running was poor. I put this down to a bit of dirt remaining in the idle circuit, especially as it would clear occassionally. It did so after a longer run on Saturday but it had no power - it crawled up hills that it normally rolls up easily!

So striped it down again, found the power valve diaphragm was faulty - not sure that this would reduce power as it appears to open a valve to richen the mixture when there is a low vaccuum.
Have replaced this, still not idling correctly and performance is still down.

Can anyone advise on appropriate jets? The ones fitted are as follows: Idle -45, Main 130/135, and air 170/125 which are roughly in agreement with what the Haynes manual suggests for a 2 litre pinto.

Incidently the engine appears to have a Piper fast road cam fitted, ignition timing is 6 degrees BTC as suggested for 1800 pinto (and 2 litre) on unleaded.

Any thoughts?

Nick

[Dane_Rescueman]

Re: Weber 32 / 36 carb jets

Hi, On my DGAV that I converted to a manual choke with the Weber conversion kit, My sizes were as follows:

Main jets:

Primary: 135 (gives economical cruise and pleasant “Pop” on overrun)
Secondary: 130 (Slightly bigger than the normal 127 for better acceleration)

Air Correction jets:
Primary: 170
Secondary: 125

My engine was basically a standard 2 litre plus a positively antique Kent FR21 cam. The carb gave good response at all speeds and revs.
With your set up, it may be that the progressive coordination between the primary and secondary throttle butterflies is out of kilter. This may need attention.
Check float level as this is fairly critical in a Weber.
Check that the acceleration valve works OK.
Finally check for any vacuum leaks too.
I suspect that the secondary choke is not operating correctly, or, as an outsider, the actual starting choke valves are out of sync.

My idle mixture was adjustable via the well hidden needle valve. This shouldn't affect normal cruise though.

It is normally a very forgiving carb. The softer Vulcan engine produces 135bhp just using the 32/36.
Make sure it is a DGAV 3D1 or thereabouts carb.

I used ignition timing of 12° BTDC on the old leaded fuel and 8°BTDC on unleaded.
Good luck with it.

[CABRIOBOB]

Re: Weber 32 / 36 carb jets

Nick,
Make sure your carb to the manifold gaskets are ok and you are using the plastic specer plate.
Make sure the manifold to the cyliner head gasket is ok. Also try the brake servo pipe to the manifold is not loosing air, you can nip the pipe with some grips to test.
Is the air filter large enough ? try it without it fitted. There is a small fuel filter in the carb just after the fuel inlet, its has a small plug 17mm spanner size fitting!.
A fast road cam can make you have uneven running at low idle speed.

[Tnick]

Re: Weber 32 / 36 carb jets

Thanks for the help -

Some more fiddling resluted in a slightly better idle.
I then was able to check the vaccuum take offs from the inlet manifold. The enginge breather connection looked tired. A new jubillee clip seemed to help.

Changing the idel jets ffor the onse in the previous carb helped a bit more.

Bob mention of the plastic spacer plate gave me someting to think about. Suddenly realised I had used the plate fitted with the 38 DGMS carb which has 2 circular holes rather than the single large hole. Went out this morning, made some new gaskets and swapped the plates. Seems to be a vast improvement! starts and idles as I would expect. Still may be a bit week as still some hesitation so may need to enlarge the idle jet. I'm awaiting suggestions from on e of the suppliers

Thaks

Nick

[copperleaves11]

Re: Weber 32 / 36 carb jets

Hi Nick. Looks like you are closing in on the problem.Regards

[fredsajs]

Re: Weber 32 / 36 carb jets

HI Nick.
Seams most people have answered your questions, however I am interested in fellow comments regards uneven running on tick-over ?.
As have simular tick-over hunting on Fr21 cam with same carb that causes engine to die if I dont sit with it till it warms up. The auto choke does not seam to raise rev when in use at all.
Any idea chaps ?.

[fredsajs]

Re: Weber 32 / 36 carb jets

Forgot to change MOC box to Yes !.

[Dane_Rescueman]

Re: Weber 32 / 36 carb jets

Hi Fred. I'm assuming that you follow the normal procedure for the auto choke. That is, fully depress and release the accelerator prior to starting. This allows the fast idle cam to spring to the fast position. Once running, using the throttle will allow this cam to release as the engine coolant warms up.

The Haynes manual is fairly accurate with the fiddly set up of the auto choke system. Have a look and see if there is anything amiss with the setting up of the spring loaded fast idle cam and its adjusting stop.

I had snags with this system and converted my carb to manual choke. The Weber guys sell a kit for this which is easy to fit. Once fitted, one pulls out the choke knob and then depresses the accelerator as before to allow the little cam to move. Obviously one would need to push the choke knob in once on the move.
the automatic system corroded away inside the white metal cover and prevented the bi-metallic coil inside from moving and this operating the choke spindle. It is possible to buy new auto choke parts but I just went for the manual option.
Cheers.

[Tnick]

Re: Weber 32 / 36 carb jets

THE SAGA CONTINUES

Saturday - car started easily - thought I had fixed it. (see earlier post)

Monday - coaxed car into life, coughed, spluttered etc. seemingly no better!

Did some research, came accross an earlier posting from Dane (Tuning out a flat spot Weber 32 /36 Dec 2008)where he suggested that there needs to be sufficient clearance between the top of the carb and the filter.

Realised I had tested it without the filter attached. Removed filter - car started - when for a drive later (no filter) much improved!

Dane suggested a gap of 1.5 times the choke was needed - only 10 mm on my set up. Looked on fastroadcars website - the filter they supply suggested a gap of atleast 13 mm.

So ordered new filter (plus a few larger jets to save postage) and converted the original filter to a Frisbee!

Regards

Nick