Paid particular attention to slow and main jet orifices with small wire. It runs good from slow idle to half throttle.I can't get it to run over 60%....keeps stalling out.
Yeah, I know that you've looked at the carburetor a zillion times BUT the above explanation indicates that the brass high speed jet located horizontally in the bottom center of the float chamber (way in back of that drain screw) is still partially clogged, fouled, gummed.
The ID of that high speed orifice is .029. If you're cleaning it in place with a wire smaller then that diameter, which is a normal thing to do, you may be missing some of the restriction. Best to remove the jet to clean it properly.
Should you need to replace it... the original part number is 310758 but it is superseded up to part number 330142. It will be marked, imprinted on its side the number 29D indicating its ID of .029.
NOTE: The 1964 3hp
does not have a slow speed orifice... it had a adjustable slow speed needle valve and is to be adjusted as follows:
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(Carburetor Adjustment - Single S/S Adjustable Needle Valve)
(J. Reeves)
Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.
Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.
Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.
When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.
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