I just replaced the water pump impeller and seals in pump and the lower end. This is a model E15RENM and it works great. Idles good and has good acceleration. Good compression in each cylinder. After I replaced the pump and seals, I put it in a 55 gallon drum with water and ran it. I had water pumping like never before. Left it idle for about 5 minutes, then throttled it up (in gear) and water splashed up on the engine, but kept running. I probably ran it for 15 minutes. Took it back into the garage, put it on the stand. Came back 5 minutes later and I have white mess of oil and water dripping from behind the prop. Now on this model the exhaust exits from there. Dropped the lower unit and this gunk is up through the exhaust. But before I dropped it, I drained the gear oil and it was clean as can be. Is there a gasket for between where the lower unit splits. There wasn't one there from new. Where is this crap coming from or is it normal? The problem lays in the exhaust somewhere but can't nail it. I didn't notice this before I replaced everything. I had ran it in a barrel before and after running it noticed a little oil dripping from the prop and that's why I ripped it down.
