When wintering my 1990 Yamaha 130HP two-stroke outboard, I added Sea Foam to the non-ethanol gasoline in my boat fuel tank and ran the engine on my driveway using a garden hose for cooling. The engine gave off a large amount of smoke, which I understand this to be normal. (?) After 10 minutes I pulled the fuel line allowing the engine to run out of gas. I replaced the plugs as some were quite fouled with carbon. My problem is, I noticed oil pooled beneath the outboard. This is an oil injected engine so am I to assume this is caused by two-cycle oil getting into the exhaust? Additionally, I’m an engineer with a background in engines.