On that mower it is common for the air filter backing plate to warp and not seal between the aif filter housing and the carb. which has to seal for the primer to work. the fix isn't to replace the gasket. the fix in most cases is to double gasket it. Try removing the air filter and looking into the carb while pushing the primer you should see gas squirt up from the bottom of the carb venturi from the emulsion tube. No gas then primer not working and won't start cold.Nope, metal. Got new one, compared to old one and all is same. Previous post suggested that gasket was not sealing/ to tight; put new gasket on and get same results. Just a hobby I got to fix and sell but this one has me puzzle.