Primer on a 3.75 Briggs & Stratton engine?

This is Jake. Thank you for your answers. I had replaced the diaphragm gasket when the engine was running erratically. A three dollar fix, and was about to sell the whole mower to the guy who fixes them for $20.00 and buy another from him for $120.00. He would have fixed it and made a nice profit!

I fixed this one as well. What happened is the fuel pump (the long piece at the bottom of the carburetor that extends into the gas tank) had fallen off. Hence, no gas when I primed it (only air) and, of course, no gas getting to the fuel line. How it fell off I don't know!! But obviously that can be a problem with these little engines.

But I have to say, for an inexpensive engine it runs quite well in spite of the once in a while easy to fix problems.

Jake
September 2009

This is a 'classic' engine. It's possible that the diaphragm between the carb and tank has ruptured - but it's more likely that the check valve inside the carburettor has stuck. This is a non-replaceable part, but sometimes a sharp tap on the carb will free it off.

If not (and the tank is full), the only cure is a new carb. Carb cleaner is not an option - it will dissolve the plastic body before it dissolves the crud causing the problem.

phil_saunders(a)bigfoot.com

Phil Saunders
September 2009

replace the rubber gasket between the back air filter plate and the carb and all should be sorted.

John
September 2009