primer leak on briggs and performance

[38racing]

I sold a push mower to a friend . Briggs 90000 series with the primer on side. This is his second summer but he said it was not running that well right now. I took him another one and picked up the old one. a quick test found it seemed to be running too slow although throttle control position (fixed) seemed ok. When I primed it there was some gas coming around the bulb outside. Will that primer leak cause a rich condition or lean for that matter but engine was not surging. I will change the primer and trouble shoot from there. Plug looked old. Maybe needs air cleaner. Guess I should have offered to check it over in the spring. But $25 for 2 summers cutting isn't all that bad.

[Mek-a-nik]

The main problem I see with that engine is rich running, chugging. The plug will be black. Sometimes just a dirty air filter, most times the culprit is the gasket and diaphragm between the carb and tank. The nylon carb warps and loses its seal with the gas tank. I fix them by using a new diaphragm sandwiched in between TWO gaskets. That seems to fill up the gap. Been doing this for 5 years, haven't had a come back.

[38racing]

Thanks. I replaced that on the unit I just gave him. It was retrieved from our church's charity dumpster. I started it with my seafoam mixture and it ran fine through the whole tank. That was unusual as normally the seafoam leans it out. When I put the fresh gas in it actually ran worse. Changing the diaphragm has it running prefect. Now did I have sense to order 2 diaphragms back then? I always seem to need a small part right after I get an order in. I ordered stuff for myself that came on Tuesday and then a friend called Tuesday that needed parts from same place. Could have saved him another $12 shipping