PICT 34 carb fuel draining and hydrolocking

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chuck c

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I'm still having trouble with the carb draining into the cylinders very fast when not running and the petcock left open. Even if I don't leave it open, it still drains whatever is in the bowl, then it's hard to start because the bowl is empty and one of the cylinders has a lot of fuel in it. This has got to stop! I've researched it and did find someone else with the problem. There are a few possible causes, some are eliminated by it not being on a VW. Heat in the engine compartment can cause Solex carbs to boil the gas and it will flow out the bowl vent into the throat. That won't happen with no engine compartment.

Another cause is the needle valve, I've tried two and adjusting them and no improvement. The only thing left is a leak in the casting itself or a passage is drilled wrong. The carb is no good. I'm on the edge of buying another unless someone can suggest something else to try.
 
Try shutting off tha petcock and let her run a minuite before you kill tha engine. Its a good safety practice for any bike.
 
[url=https://classicgoldwings.com/forum/viewtopic.php?p=183002#p183002:a239h8cu said:
BikerJoe » Sat Oct 29, 2016 11:58 am[/url]":a239h8cu]
Try shutting off tha petcock and let her run a minuite before you kill tha engine. Its a good safety practice for any bike.

Yeah, that will work but it's a poor solution. That's what I'm doing until I get it fixed properly. Same problem with it taking a lot of cranking to refill the carb tho an electric pump would fix that.
 
ok chuck ...with the vw carb on a bike the float has to be lowered more from any info you will read to set it.....cars basiclly sit level ...parking your bike on side stand is enough for the bowl to spill over and leak into motor ....my float on hooches dft carb is set quite low ....and i neve use the side stand ever ...and have no problems ....i am lucky to have the front ride off stand and it all easy for me ....but yes id say lower the float ....as corners can cause gas to flood the carb .....
 
Doubt it but check for pressure in the tank.

I'd check the casting for leaks on the bench with the bowl full.

Other than that try lowering the gas level in the bowl as suggested. I lowered mine by 1 washer.
 
Yeah I'm using the center stand from now on too. I have a ride-off and will get it on someday. But still, I should not have to. Even if the float is set low and the valve works, it means nothing if fuel is somehow getting out of the bowl. It will just refill as it's supposed to. Somehow fuel is getting from the bowl into the intake by a path it shouldn't have.

There most definitely is pressure in the tank but I was led to believe that's normal.
 
i dont the vw carb well but a weber has passages where the gas will flow into carb and in motor if the gas gets that high ....im rathe sure your carb is like that too...but dont know for sure...... as far as start up on mine ...if the gas tank is not like complete full ...the line will drain back into tank and will have to crank it longer to fill the line back up
 
The Solex has a vent from the bowl to the throat. It's a brass tube at an angle. It's very easy to see. Pretty much even with the very top edge of the carb. I used it to prime the carb a few times. If the needle stuck open for any reason and the fuel kept coming, it would overflow that straight into the engine. I think that's the only overflow.
 
Because most motorsikels are gravity fed and the needle valve is the only thing stopping gas, their carbs usually have an overflow tube so in case they don't work and the dummy rider forgets to shut off the petcock, fuel will run onto the ground and not into the cylinders. On a single carb Goldwing at least some of the tank is still higher than the bowl and fuel can seep past the pump. This might not be a problem if the fuel in the tank is low enough to be below the bowl.

One solution: raise the carb high enough that it's bowl is higher than the tank. Not doing that!

I'm going to remove the top of the carb which includes the float and valve, fill it with gas, put it on the centerstand, and see if the level drops.
 
Pic 1, Filled with gas, float level. Pic 2, <10 minutes later.
 

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These pics are about 20 minutes apart. Where the heck is my gas going!? Well, I know where it's going, how is it getting out of the bowl?
 

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hmmmmmmmm gas is leaking out.....well i dont know the carb but its time you figure it out .....cant be to many places it can go out ...you need to take carb off and repeat test and see where its leaking
 
well there sure is a feed somwhere for it ...need to look at idle circuit also ...they are useally high up on carb and exit low ...it could be syphoning gas out of bowl from its feed point in the bowl maybe......gas level in the pics looks like a feed hight to something ...
 
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