John In Ct re: Marvel

A bones

A bones

Well-known member
Hey John,
Since you can't receive a PM,, I figured to reach you this way,
Your post about your carburetor wound up on the Model T forum.
Repost here for faster service.
 
I have a Marvel Schebler carburetor on my A. When I first start my engine I pull the choke for 2 revolutions and it starts up perfectly and runs smoothly
When I’m pulling the choke rod gas is leaking out of the air intake from the carburetor not much but enough. Is this normal? I did install a new rebuild marvel Scheibler and it’s doing the same thing. I do set the float level to spec. I don’t remember what the spec is but I got it from Renners corner
 
John, if you run the carburetor with the GAV open, when you start up the engine, it is getting gas from the main jet and the Comp jet. The Comp jet is releasing more gas then is needed to start the engine, so you see the excess dripping from the bottom of the carburetor. Try closing the GAV during startup and see if that stops the carb from dripping.
 
AL in NY said:
John, if you run the carburetor with the GAV open, when you start up the engine, it is getting gas from the main jet and the Comp jet. The Comp jet is releasing more gas then is needed to start the engine, so you see the excess dripping from the bottom of the carburetor. Try closing the GAV during startup and see if that stops the carb from dripping.
Click to expand...

No comp jet in a Marvel Schebler...

When I start my Town Sedan that has a Marvel I open the GAV ~¾ turn, no choke. Starts right up. Once warmed I close the GAV to ¼ turn open.

I set the level ⅝" below the gasket surface. Level gauge available from Renner's Corner.

511105
 

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Check and adjust float level as previously mentioned. Also check needle valve and seat for signs of wear - carb can leak into the intake tunnel or out the bowl vent if too much fuel is getting into the float bowl. Renner's Corner has the parts you need.
 
See the Y Block's photo of the little red gasket at the choke driver into the lower casting. Sometimes these are missing. Also, the choke needle has a little rubber type of ring near the tip, which can be missing, etc. The ethanol gas isn't too friendly to it. This seal may have been leather or some other material originally but not sure of that.
The float valve may also not be sealing properly, so a well operating fuel shut off valve is good insurance when the engine is not running.
 
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The Marvel carb has what looks like some graphite packing at the very bottom of the GAV needle valve well that helps seal around the needle valve. You might check to see if that packing is there along with the felt seal, spring, and brass washer. These parts are in the rebuild kit that Renner's Corner sells.

https://rennerscorner.com/carburetor.html
 
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