The Stovebolt Site Forums The Shop Area Engine Shop Engine stalls on heavy throttle

I had to replace the accelerator pump one more time AFTER I rebuilt the carb, there was just too much varnish and debris in the old tank, lines, and fuel pump, now the whole fuel system is new or rebuilt and it starts and runs very well. The accelerator pump gives a shot of fuel down the carb throat each time you push the throttle, if it's not squirting fuel when you manually operate the throttle then you will get the symptoms your describing.