I have a 1975 M-700 with a VH4D gas engine. I've gone through it thoroughly by doing a tune up and carb rebuild. Also flushing out the fuel tank and installing an electric pump (3-5 psi). It pulls great vacuum at idle (21"). My problem is that when I'm really bouncing around working, it will stumble badly but then pick back up like its flooding. I set the floats to specs when I rebuilt the carb. It has the updraft Zenith carb. Is this just the norm for carb engines or is there a solution out there? Thanks guys!