Looking for carburetor help

1967806 · Jul 15, 2020

Working on a Massey Ferguson 150 with continental engine. Replaced exhaust manifold and rebuilt carb while it was off and now it wont idle unless you pull the choke out slightly and have the idle screw turned all the way in. Only thing that I could see that I didn't care for while it was apart was the veturi was pretty loose in the upper housing. You could see a little daylight around one side of it depending on which way you held it. Just wondering if that would be the problem or something else. Any ideas?

Steve@Advance · Jul 15, 2020

The ventura should fit snug, and will only go in one way.

If it's the wrong one or in backward, (which I don't think it will even begin to go), it could be holding the top from sealing to the bowl.

The idle fuel is drawn up the small hole beside the ventura. If that is not sealed, or the wrong gasket, or the gasket torn, it will not draw up idle fuel.

1967806 · Jul 15, 2020

I ended up taking it back apart and turning the venturi around and it made it idle better but still dont suit me. When I was cleaning everything up after it came out of the carburetor bucket my fingers looked like they had never seize all over them from it. Im thinking it's letting something around the outside. If I could find a new venturi I would sure try it.

Steve@Advance · Jul 15, 2020

If the screws were tightened down with the ventura upside down, it may have warped the top so the 2 pieces don't tighten down on the gasket in the center.

If that happened the passage that draws up idle fuel will not seal, and will not draw up steady and sufficient idle mixture.

If it's warped it can be taken apart and filed flat.

When setting the idle mixture, remember on that carb turning the idle mixture screw in richens the mix, out leans it. You are adjusting air bleed, not fuel flow. The adjustment is minimal, and is only adjustable with the engine at slow idle, 500RPM or less. If idled down, and the screw makes no difference, there is a problem with the idle circuit.

Keep in mind the carb function is totally dependent on all other aspects of the engine. If the compression is low, the ignition system is not in tune, the carb can't function properly.

Is the fuel fresh, clean and water free? How is the air cleaner? There is a wire mesh inside that needs periodic cleaning, and is often forgotten. How is the oil? If it is fuel contaminated it will influence the carb adjustment.

Keep after it, you'll get it right!

Looking for carburetor help

1967806

New User

Steve@Advance

Well-known Member

1967806

New User

Steve@Advance

Well-known Member

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