1971 Bus - Fuel Odor

bus71 · Post by **bus71** » Sun Dec 16, 2007 10:56 pm

My bus is a 71 1641 svda with stock 34pict carb(german) Recently developed a leak due to bad accel. pump. Rebuilt carb. including new top gasket and needle valve. Noticed gas leak at top gasket. Put on my spare 34bocar with new kit. Same problem. If I tip either carb, gas soaks gasket. Carb. removed, float level correct. I have stock fuel pump, about 2yrs old. I have never used sealer on carb gaskets. I don't know origin of 1st carb kit, 2nd was borg/warner(all I could get). The engine and carbs run fine except for leak. Any help, ideas would be great! I'm stumped! It seems that normal driving, cornering, etc cause gas to seep from top gasket. Thanks!

hambone · Post by **hambone** » Mon Dec 17, 2007 10:19 am

Something is obviously not right...I'd not run a car with a leaky carb, fire city!
Don't think you need to use a sealer. Not sure but it sounds like the rebuild kit isn't being done correctly or the bowl is getting too high for whatever the reason.

bus71 · Post by **bus71** » Mon Dec 17, 2007 12:20 pm

Thanks, I'm working on it, not driving it and appreciate your concern. I have an alternater with correct fuel pump and short push rod. I"m wondering about rod adjustment. It can't be 13mm as shown in bently since alt. rod is shorter. This is recent problem that I haven't had before. Been driving this bus a long time and have rebuilt carbs many times, which doesn't mean I'm not making a bonehead mistake but? Thanks!

Post by **Amskeptic** » Mon Dec 17, 2007 6:57 pm

Verrrrrrrry carefully slide carb top piece across a fine sandpaper 600g that is firmly drawn tight across a piece of mirror glass. If you see uneven contact marks, you have warped top. See if you can mill it down without screwing anything up. There is a piece of brass sticking up on my PDSIT carbs for the accelerator pump that would make "sandpaper milling" very difficult. I hope yours is a straight shot.
The carburetor body same deal, but you must figure out a way to prevent contamination of the passages and bowl. If both surfaces end up perfectly flat, reassemble and tighten only in a cross pattern, like a wheel.
Ask yourself some obvious questions like "did the drilling plug for the accelerator pump passage pop out?" It is a very tiny plug. that installs sideways. Once all is assembled and the bowl is full, can you check for fuel integrity by pumping the throttle lever as though to flood the engine (you will) and see exactly where this fuel is coming out?
Colin

bus71 · Post by **bus71** » Mon Dec 17, 2007 11:05 pm

Thankyou, both my old carbs are warped. the top and bottom don't mate close enuff for the gasket to seal. I'm going to give the milling a try. I used HiTack sealer carefully on the edges of the bocar top gasket. I will test in the morning but not much hope. I'm going to work on milling the german as a slow, patient project. ( it was my favorite carb) Any thoughts on useing 2 gaskets? Thanks!

Post by **Amskeptic** » Tue Dec 18, 2007 8:59 am

bus71 wrote: I'm going to work on milling the german as a slow, patient project. ( it was my favorite carb) Any thoughts on useing 2 gaskets? Thanks!

Excellent answer on choosing the German carb. Mill away. It is fun Black Forest Elf German Craftsman Bonding Behavior. VWs respond very positively to such things. . . two gaskets on the other hand, see me after class.
Colin

hambone · Post by **hambone** » Tue Dec 18, 2007 11:24 am

A warped plate, I never woulda thunked it..

Itinerant Air-Cooled

Itinerant Air-Cooled

1971 Bus - Fuel Odor

1971 Bus - Fuel Odor