Marvel Schebler carb pouring gas

rivcokid

rivcokid

Senior Member
I got a Marvel carburetor for my 4-door because I liked what I heard about them. It came (supposedly) all ready to go but when I bolted it on, hooked it up, and turned on the gas, gas began to pour (not drip - pour) out of the air intake. I pulled the carb apart and it seems like the float is healthy and the pin is there, but something is not allowing the gas to stop. Anyone familiar with this issue or these carbs? Please see attached pic - I wish we could attach a short video so you could see what I mean!
 

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Take the carb apart, remove float pivot pin, remove float valve needle, is it clean? Clean with brake cleaner. Look at valve seat is it clean? blow out with compressed air and clean with brake cleaner. If both parts are clean, lower float 1/16 to 1/8".
 
Herb is right. The only thing that would cause that is the needle valve not seating correctly. Possibly the float level is wrong, but most likely something between the needle and the seat.

After you clean out whatever is holding the needle off the seat, you can test it by holding the float against the needle, same as the gas would and blowing (with your mouth) in the inlet fitting. If you can't blow air through you're good to go. Get an inline filter in the system somewhere. You'll like that carb. Much more modern design than the Zenith or Tillotson.
 
Make sure it is the correct valve and needle. I had a homemade need and seat.....yeah it didn’t stop the gas from flowing.

Mike
 
If you bought the carb from a re-builder/vendor, call them before you mess with it much. They may have suggestions, or may exchange it for a different one.
 
Before you take it apart shut the flow of gas off, start engine, run till it stops, turn gas back on----- there's a good chance that the debris will get washed through, if still has the problem after doing this 2 times then there may be a internal problem
 
It doesn’t take much fuel to leak into the float to make it sink. My MS started pouring fuel out the intake. I removed the float which looked ok and put in the float bowl full of fuel holding the float arm. It promptly sunk. I could barely discern the fuel sloshing inside the float.
 
Hi all - thanks for the ideas. I did buy it from the guy in Texas but I bought it in February and only now put it on so I feel a bit guilty asking him to "make it right" although he offered more than once on the phone. I did to the "blow" test and it's sealed - I could not blow through it. It is all clean and rebuilt - practically brand new so it's not an issue of dirt or grime. I'll keep you updated!
 
41plym said:
If you bought it from the guy on eBay out of Texas contact him and he will make it right without question.
Click to expand...

His name is Jim Bullock. He could not be a nicer guy. If you can't get it straightened out contact Jim. He will make it right.
 
Probably not your issue. Once in a while especially if you have been working on it, or its been laying on its side, or if you just gone through shipping, or have piece of something in the float valve - tthe valve does not seat properly. Can try tapping the float bowl with the handle end of a screw driver. Sometimes it is all it takes and all is good.
 
Believe me JR Bullock would want to know about any problem with his rebuilt MS carb. He will go to any extent to fix/make it right - ask me how I know. You are just one call away from making a good friend who is knowledgeable AND capable when it comes to Model As.
 
If Zenith carburetor leaks like this after being shipped (or in some cases after being laid on its side) is common in my experience.


Might work with other makes of carbs also.



If it leaks, turn off gas shutoff valve.


Use gasoline in float bowl to run engine for short time.


Rev it up a couple of times.


In most cases the vibrations will re seat the float valve.



THEN turn shutoff valve back on and watch to be sure leak has stopped ... in most cases the leak will stop.

If not then something might be wrong inside carb.

Hint: If you need to tap on a rebuilt painted carb try hitting it on the Strainer HEX fitting instead of the paint.

Replacing the "dented" strainer is much easier than disassembling and re painting! (Powder coating)
 
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I had that happen with a MS carb several years ago, and could never figure out what was wrong or get it to stop. I eventually just took it off, put it on a shelf, and installed a Tillotson on my car. I'm no mechanical engineer, but I think the float on the MS carbs is too small. Just an uninformed theory.
 
wmws said:
His name is Jim Bullock. He could not be a nicer guy. If you can't get it straightened out contact Jim. He will make it right.
Click to expand...

Agree. I have one of Jim's MS carbs and it is great, he is a good guy knows his stuff and stands behind his work. I'd highly recommend him to anyone in the Model A community:)
 
Update - I spoke to Jim and just like you said, he was very interested in what may have happened and quite willing to send me another for an exchange. I may be getting it today or tomorrow. Will keep you up to date. PS - I did do the "blow test" and could not get air to penetrate the valve, so it seems to be seating correctly (on the original carb that is now on its way back). Will check the new one when it comes, naturally, and watch for the additional ideas you've provided. Will let you know! Thanks
 
Did you check the float submerged to see if air comes out a pinhole, as referenced in post 8 ? I've soldered holes after heating the float with a hair dryer or similar to dry it out.. It also only takes a spec or so from the tank / filter bowl to lodge in the valve tip. Some of us shut off fuel and run the carb almost dry at shutdowns.
 
Update again - Hi all. I received a replacement Marvel carb from Jim yesterday and installed it today. What a difference! The car does run much better and I don't have the issue I had with it almost dying on me if/when I had to hit the brakes (and the Zenith was clean, so to me it was a design issue not a clean issue). Anyway, bolted the new carb on quickly, turned on the engine and let it run for well past the time that I had the original Marvel on, and no leaks, no issues. Would recommend highly so far! Thanks again for all your suggestions!
 
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