weeping Weber ???

[C. Clark]

Hello to all,
I have a problem I can't seem to solve, perhaps you can help. The passenger side Weber has a intermittent leak or weep. In between the barrels, underneath, where the butterfly shafts pass from barrel to barrel, gas runs down the spring/shaft that works with the accelerator pump, and I get an occassional drip. The drip manifest when the engine is not running and varies in the intensity. I've checked the accel. pump, float level, visual inspection several times. The other one does not leak; the leak is not severe just a pain in the ass and has become very frustrating. Any ideas are greatly appreciated.
I'm beginning to think it's a pressure / vacuum thing with the plumbing...
Thank you,
Chas. 69/912

[Tom Perso]

It could be there is some slop in the throttle shaft and the carb body. There is no real seal in that area, it's just a tight fit. If it's worn, you can get a leak. Is that side running leaner compared to the others?

Other than that, *maybe* a cracked carb body??? I doubt it though.

I assume you've got new gaskets and such on it, and fuel pressure is no more than 3-3.5psi?

Just throwing out ideas...

Hope this helps,
Tom Perso

[C. Clark]

Thanks for the input, I run an elect fuel pump with a regulator, 3lbs. Bob Tomlinson's manual says 40 idf should have the float set at 10mm from the top of the float chamber, I think I'll increase and see what happens.
Thanks,
Chas. 69/912

[Green 912]

Float levels effect the enrichment across the upper RPM range. Webbers use emulsion tubes and are sensitive to the fuel level. Higher float bowl levels will run richer.


Is the fuel in the float bowls boiling during shutdown and spilling into the throats? This could be happning and only showing on the passanger side.

The accell pumps are also a common leak point. The rubber disk is an inexpensive part. ($2) I see that you checked them but it might be worth replacing them if they are old. From the reported symptoms I would start there.

Also look and see if the leaking gas has washed the grease from the accell pump spring. If it is dry the pump lever will grind the little guide tube and then the pump will start to pump poorly. BTW the little tube can be a pain to find.

I used a word (a term for a female K9) that the BBS did not like, resulting in the following....

[C. Clark]

Kurt,
Do you have a good place to get Weber parts if needed? The accell. pump is not leaking, gas is not boiling in the float chamber. It's so weird, it's like the gas is being syphoned, or drained from the bowl. Yesterday I took the top off and the bowl it was nearly dry.
Thanks,
Chas. 69/912

[Green 912]

PMO. I don’t have the phone # in front of me but they advertise in excellence and Pano. Let me know if you can't find it I have it at home.

PMO can be somewhat of a pain to deal with compared to part houses with 800 #s as you have to start any transaction with a fax. Put your questions and or parts needs on paper and fax it to them. They will call you back and they WILL give you good advice.

It is hard to tell without seeing the leak. Have you checked the lead plugs? They have a bad habit of comming out. I now chinch them up and put a dab of RTV on the ends of all 4 when I have the carbs out. I have seen them come out twice and both times much fuel was pumped into the engen compartment. I had one pop out on the track, I checked and found 1 more that would sometimes leak when you wiggled it. I will have to go fish one out and look to see where fuel might be able to leak out.

[C. Clark]

Kurt,
Thanks for the info on parts, the situation that makes me nuts is the intermitency of it. It like something every so often sticks open. I was thinking it could be that one way valve in the bottom of the float bowl, it has a ball stop with a spring. I may switch with the other carb and see what happens, I'm afraid it's down to stuff like that.
Thanks for the time,
Chas. 69/912