Stop Quick, engine dies

[daveymc29]

Friend called today with the above. I'm sure it has been addressed several times and hope I gave him the correct answer. I told him to lower the fuel level in the float bowl to not higher than specs. If that is correct let me know. That is how I remember it when I had the same trouble, but I didn't find a thread.

[Synchro909]

David, I would have given him the same advice.

[Jacksonlll]

First and easiest thing to do is flatten the surfaces between the carb flange and intake manifold flange. I'm sure you will find them warped a bit. I have fixed several doing just this. All you need is a big file, a light and mirror and a new gasket.

[Mulletwagon]

Had the same problem despite proper fuel level. Fixed problem by blowing out the idle passage and jet with carb cleaner. The passage goes from the idle jet in the bowl, up the top half of the carb, and exits right at the throttle plate. Also important to adjust the idle mixture properly. Set idle speed to minimum, retard spark, and turn idle mixture screw for best idle. Usually setting the idle speed higher to avoid stalling does not work since the high speed jet kicks in and the reduced vacuum at the idle port is too low to pull fuel.

[Bob Bidonde]

When stopping quickly, the gasoline in the float bowl surges forward uncovering the passage to the Compensator Jet, and uncovering the passage to the Main Jet & GAV. It is likely that the Idle Jet Well retains some gasoline, but the Cap Jet and Main Jet will starve causing the engine to run roughly / stall.
To remedy the uncovering of the passages to the Compensator and Main Jet, the gasoline level in the float bowl should be increased.

[History]

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Nice diagram Bob, thanks for posting that.

Originally Posted by Bob Bidonde

When stopping quickly, the gasoline in the float bowl surges forward uncovering the passage to the Compensator Jet, and uncovering the passage to the Main Jet & GAV. It is likely that the Idle Jet Well retains some gasoline, but the Cap Jet and Main Jet will starve causing the engine to run roughly / stall.
To remedy the uncovering of the passages to the Compensator and Main Jet, the gasoline level in the float bowl should be increased.

[30 Closed Cab PU]

Here is a link


https://www.modela.org/engine_dies_stop.html

[History]

My brother was telling me yesterday about a 135 Massey ferguson tractor he has that is gasoline powered. He rebuilt the carburetor and like on a zenith thought he had a leak and over tightened the drain plug and cracked the bottom of the carb. He was helping an old fellow who bought salvaged material and junk equipment and he was junking something that had the same carburetor on it. He was able to get it and used the bottom on his. He said the Venturi was smaller and the tractor ran the best it ever had. Are there any problems with the zenith carburetors having adifferent sized Venturi? Do they wear and the throats gets Larger?

When I rebuilt mine I got an original Venturi from Renners corner that had been blasted to clean it, can't remember what was used for the media. I also ordered a new one from Snyders and there were differences that I can't recall but were noticeable. I didn't mic the inside diameter.

[jquinlan]

Before you do anything, open the Gav up and experiment. Myself AND another friend of mine had the same problem with our cars recently which went away after opening up the GAV a half to a full turn more.

[PalAl]

Bob, very well explained and a great diagram showing what happens. Thank you