If i remember it is 5 to 7 psi at the water jacket vaporizer

Thanks everybody for info. It was the vaporizer

Does the vaporizer go into the top water housing where the top hose goes if so it is a zenith vaporizer there is a allen screw at the top that is were you check the gas pressure it is around 8to 12psi any more and the vaporizer is bad also the carb could cause to blow gas through must check at vaporizer first hope this helps.

A specific vaporizer that goes on. must make 20 psi for it to run correctly. Waukesha engines only.