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'56 235 with Rochester 1bbl

Engine starts fine. While trying to move forward or reverse the engine sputters and stalls.

I hve replaced spark plugs, distributor cap and distributor rotor. Engine idles better than before.

A hissing noise comes from carbirator when throttle is applied while letting out clutch.

I'm guessing a carb rebuid/check is in order.

All suggestions are welcome.

1st swag is you've got a vacuum leak.
If you aren't running vacuum wipers make sure the vacuum tap on the intake manifold is capped off.
Make sure the vacuum line from the carb to the distributor is tight and not leaking. You can test it by disconnecting the line and plugging it at the carb. You'll get a hesitation but shouldn't stall.
Make sure the carb nuts and the intake/exhaust manifold clamps are tight.
You may need to use either carb cleaner or a hand held propane torch to further check for vacuum leaks around the carb base (throttle shaft) and where the manifold bolts to the head.

edit, does your carb have a manual or automatic choke?
Make sure it fully opens when you try to drive it off.
Another test to try is partially close the choke when you put it under load to see if it runs better. If it does you've isolated the trouble to the carb and narrows it down to either a vacuum leak or feul issue.


2nd swag is you're not getting enough fuel.
Disconnect the fuel line at the carb, while pointing the line into a container of some sort, have someone crank the engine. You should oberve pulses of fuel squirting in to the container, dribbles or very short/small pulses of fuel indicate eithr a bad pump, clogged fuel line, a clogged hidden fuel filter under the vehicle or debris cloggng up the tank.

I wouldn't tear into the carb until you've done all the easy checks.

Good luck
Dave

Dave,

Thanks for the input. I will check those things out.

The choke is manual and it runs better with a partially closed choke.

Stay tuned.

Check the timing as well.

Mine exhibited similar symptoms, and timing was set more or less on the flywheel mark. Advancing it a little improved a ton.

I had a similar problem with hissing from the carburetor and poor performance under load. It turned out that the bowl on the Rochester B was warped just enough to suck in some air and make a hissing sound. I resolved it by changing to a Carter YF.