1991 Yamaha 9.9 issues. Model T9.9 ELHP

[Old Drifter]

I just bought 9.9 a couple weeks ago. It was running smoothly but occasionally fouling a plug. I pulled the oil dipstick and oil spewed out. It was not milky which makes me think gas was entering the crankcase. Any Ideas on what would cause this would be appreciated. The model is T9.9 ELHP. Also discovered it didn't have a thermostat. I assume that could have caused the plug fouling?

 

[99yam40]

no stat could cause the 4 stroke to make oil because it was running too cold