I have a Craftsman lawn tractor with a 17 hp OHV Briggs model #311707-0132-E1. I seems to run fine until I start mowing. The added pressure on the engine from the cutting is creating a huge cloud of white smoke. It stops as soon as I stop the blades and put it in neutral. I assume oil is getting into the combustion chamber.

Is this repairable or do I need to replace the engine?