Small Engines (Lawn Mowers, etc.): Briggs & Stratton, briggs and stratton, briggs stratton

Question
Hi Tom - I have a Briggs and Stratton Quantum I/C 60 12J802-3136-B1. I have been keeping it running successfully for years, but have come up with a problem i am not familiar with. After about 30 to 45 minutes of use, the engine knocks a bit and then quits.(slowly) I have checked the oil level, made sure that there is no debris on the fins. I have checked the plug and the air filter. I don't think that it is overheating, but can't be sure.....do you by any chance have any good suggestions? Kind Regards, Spencer - Cape Town.

Answer
A couple of preliminary checks you might try. Check when it stalls out for spark, fuel, and compression. Start by removing the spark plug, put the lead back on and ground the side of it against the block for a good ground, have someone help you by pulling the rope looking for spark. If no spark it's a bad ignition module. If good spark, move on to the fuel system. Remove the fuel line at the carburetor does it have good flow? If not remove the fuel cap, it may have a bad vent cap causing a vacuum in the fuel tank after running awhile. Still not a good flow, continue up the line towards the fuel tank to locate a potential blockage. At sometime without burning yourself try when it is cool enough to have someone pull the rope with your thumb over the spark plug hole to see if the compression is strong enough to blow your thumb off the hole, if not the engine is tired, and lacks enough compression when it gets hot.   A few things to try then let me know the results we can go from there. These things must be done right when it quits for best test results.   Tom