super a misses under load

[keith49 sa]

hi everyone would anybody have a idea why my 49 super a starts missing when it is under heavy load? I have gone through the carb and all is fine was wondering if it could be ignition? timeing or week coil it only does it with throttle wide open or if it has been working for a while like draging a big garden. no load just driveing around it purrs like a kitten. thanks for the help guys

 

[El Toro]

I would check the valves for clearance. You may have one too tight when it gets hot. Set them at .017" Cold. You could have a sparkplug that's causing the miss. I would install a new set. Hal

 

[Carl Grover]

My M was doing that I had a bad retainer on a valve spring, it finally got to the point it missed all of the time.

 

[Andy Martin]

Replacing the ignition parts is cheap. If that does not solve the problem, I'd look for a fuel restriction. Your description indicates it misses under high fuel flow conditions.

Does the choke help the miss or hurt it? If the choke helps then look for a fuel restriction like debris in the inlet to the sediment bowl.

 

[rustyfarmall]

(quoted from post at 06:44:01 04/07/10) I would check the valves for clearance. You may have one too tight when it gets hot. Set them at .017" Cold. You could have a sparkplug that's causing the miss. I would install a new set. Hal

My thoughts exactly, except I would set the valves at 0.020" cold. That way they will be at 0.017" when hot.