Hello I have an older 2hp 2stroke Yamaha that is recently expelling a substantial amount of oil in the water. More so than what I remember. We have gone thru and have run 50:1 and 100:1. The impeller did go out and the engine did run hot but did not seize. it was serviced with no indicated problems from the shop. Question is could the heat have warped the cylinder slightly to cause more oil to pass through? Also, if the cylinder and the piston are good (it runs and idles great), would a treatment like sea foam potentially remove any carbon buildup in the cylinder/rings that could possibly be causing more oil pass through?