Good morning All, yesterday I started up my 5411 for the first time this season. I replaced my water pump ( oberdorfer) and replaced some of the hoses, along with a new thermostat. I hooked up a "fakeleg" to the intake on the hull for fresh water and started the engine, i wasnt getting the water out of the exhaust like i like to see so i turned up the water pressure. Almost immedialty oil bubbled out of the engine. I immediatly turned off the water and cursed my act of stupidity. After i have calmed down , I drained the oil, poured a little seafoam down the fill to clear out any more water. Let it drain for 15min and refilled with 15-40 rotella. I started the engine back up and she purred and ran smooth, while i had the intake hose in a 5 gallon bucket. i ran the engine long enough to run 10 gallons through, all the while stopping and checking the oil level to make sure that it wasnt increasing due to water. Here are some of the things i did wrong. I used a marine thermostat from napa (140deg) and didnt buy a factory thermostat, and i increased the water pressure to have more flowing from the exhaust. The new impeller/pump works awesome but im curious why more water doesnt come out the exhaust, rather cycles back into the raw water intake thruhull. I am really hoping i didnt destroy my head gasket . Ill keep everyone posted, Shannon