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Wed Jul 10, 2019 11:52 am

The carb on my 67 has a habit of sticking. If i press the gas to set the choke the butterfly stays wide open. The cable is free, it's the shaft through the carb that's gummy.

I've tried white lithium grease and even motorcycle cable lube. Both work for a little while.

So, is there a known product that works? A certain procedure for lubing? I've just been spraying around both ends and working the arm.

Another issue that is not helping is that my carb tends to spit gas down the throat while sitting, thus soaking the butterfly and likely rinsing out whatever lube i apply.

Wed Jul 10, 2019 12:19 pm

jimdubs wrote: The carb on my 67 has a habit of sticking. If i press the gas to set the choke the butterfly stays wide open. The cable is free, it's the shaft through the carb that's gummy.

I've tried white lithium grease and even motorcycle cable lube. Both work for a little while.

So, is there a known product that works? A certain procedure for lubing? I've just been spraying around both ends and working the arm.

Another issue that is not helping is that my carb tends to spit gas down the throat while sitting, thus soaking the butterfly and likely rinsing out whatever lube i apply.

A drop,of motor oil occasionally on the carb moving parts and linkage can help reduce wear, but if it is gumming up, I think it needs a rebuild, examine for worn or bent parts. continued running like this could cause damage. follow procedures in the Official VW Service Manual for rebuild, adjustment of float bowl level, and accelerator pump volume. Best to check fuel pressure before the float bowl level is adjusted.

the carb butterfly should move freely, even when dry of lube, so something is bent worn or dirty.

Bug On!

Wed Jul 10, 2019 12:27 pm

Gasoline is a powerful solvent that will quickly break down most common lubricants. Probably need to remove the throttle shaft and clean it with some fine emery cloth. Having the carb body re-bushed wouldn't be a bad idea either.

You also need to stop the fuel leaking into the carb throat after shutdown. Check the condition of the needle valve and the fuel level in the float bowl. With the top removed, the fuel should be about 3/4" down from the edge with the float in place.

Are you running the stock fuel pump, or an electric version? You might also check for excess residual pressure in the line after shutdown.

Wed Jul 10, 2019 1:10 pm

rcooled wrote: Gasoline is a powerful solvent that will quickly break down most common lubricants. Probably need to remove the throttle shaft and clean it with some fine emery cloth. Having the carb body re-bushed wouldn't be a bad idea either.

You also need to stop the fuel leaking into the carb throat after shutdown. Check the condition of the needle valve and the fuel level in the float bowl. With the top removed, the fuel should be about 3/4" down from the edge with the float in place.

Are you running the stock fuel pump, or an electric version? You might also check for excess residual pressure in the line after shutdown.

for reference the float bowl level for the 30PICT-2 is 19.5 +/- 1.0 mm from top of lower carb body, not including the gasket. This per VW Factory Service Manual. Thats about 0.77 inch. as stated above 3/4 inch is within limits.

Check for a flooded float by forcing it down under hot water, just below boiling. it is is fuel of gasoline, it will bubble vigorously. cold water will not work, it has to be hot, the heat vaporizes the gasoline if present, causing the tell tale rapid bubbles flowing out. even a float that seems fine should be tested this way, its part of a proper rebuild. accelerator pump volume is 1.05 to 1.35 cc per stroke. note replacement diaphragm may have a different lifter length, and this will effect the volume, so check it even if it was ok before, if you replace the diaphragm.

Bug On!

Wed Jul 10, 2019 4:06 pm

Thank you guys for the info. I will look further into the gas issue first. I bought a pressure gauge some time ago but didn't install it yet because I couldn't find a proper sized fitting for it, one that the tiny VW fuel lines will connect to.

I am running a mechanical fuel pump, looks similar to the one WW offers on their website. The residual flooding issue seems to be heat related, worse on hot days, better if I open the engine cover as soon as shutting off the engine.

Needle valve is new, seems to function based on trying to blow air through it. I will recheck float condition and level next. Any recommended source for bushings and associated rebuild parts?

Wed Jul 10, 2019 4:47 pm

jimdubs wrote: Thank you guys for the info. I will look further into the gas issue first. I bought a pressure gauge some time ago but didn't install it yet because I couldn't find a proper sized fitting for it, one that the tiny VW fuel lines will connect to.

I am running a mechanical fuel pump, looks similar to the one WW offers on their website. The residual flooding issue seems to be heat related, worse on hot days, better if I open the engine cover as soon as shutting off the engine.

Needle valve is new, seems to function based on trying to blow air through it. I will recheck float condition and level next. Any recommended source for bushings and associated rebuild parts?

bushings require machining the carb to accept them. for rebuild kits, I dont know, but like I stated, some accelerator pump diaphragms have different length lifters, thus you must ,measure and adjust as needed the volume per stroke, even small several 10s of thousands of an inch difference will have a significant effect on pump volume.
the cover gaskets can be different thickness, and that effects float bowl level, as does the float valve design and its gasket.

Bug On!

Wed Jul 10, 2019 4:56 pm

Rebuild kits usually just consist of gaskets, rubber parts and maybe new mixture screws & a fuel inlet valve. For a proper re-bushing of the throttle shaft, it’s best to send the carb off to Tim at Volkzbitz. He can also rebuild the entire thing and it’ll be better than new.
https://www.volkzbitz.com/

Wed Jul 10, 2019 4:57 pm

rcooled,

perfect, thank you!