I was pushing 70 salmon, two men, and about 30 gallons of water back to the bridge on the Kenai during dipnetting season. The load had the little motor working hard. The rear crank case bolts became loose. I soon discovered this when my motor wasn't getting gas because the pulse pump operates off crank case pressure. I caught it in time and tightened up the three top crank case bolts. Lost a little bit of oil, and the gasket was damaged. Luckily, there is zero damage to the internals of the motor. I'm going to use locktite on all the bolts when I torque them down. I'm uncertain if gasket-maker will work, but I've no time to wait on a real gasket.
Reach back there with a wrench, and check those bolts occasionally, most of these small briggs, lct, kohler, and honda motors has a crankcase with bolts: