This started 2 years ago - since that time I have rebuilt the power head because the rattle was thought to be a rod bearing due to having had the oil injection fail. Then removed the oil injection and started using premix. The engine ran like a champ! No issues for three weeks then coming into the marina I throttled back and it started the rattle/knock. After conferring with several people the majority opinion was a rod bearing due to the oil injection issue most probably. Tore the power head down and after two separate visuals was determined there was no issue with the power head - it was in great shape. So on a suggestion drained the gear lube from the lower unit and it was striped. Appeared to have water inside. Under warranty so sent it back and it was either repaired or replaced. Since the power head was already dismantled decided might as well rebuild it - new rings - cyclinders honed - new rod bearings crankshaft seals etc. Engine ran great on cranking. Replaced the main gasket between the power head and the exhaust adapter plates. Put it back on the boat and when put in the water got water leaks and the engine stalled and died. Cleaned and regasketed both adapter plates, the exhaust tuner and driveshaft housing. Put it all back together and again the engine cranked and ran good. Put it back in the water and was right back where I had started. The engine was running, water seeping from the adapter plate, powerhead gasket area and possible the lower adapter plate but the engine didn't stall or die - and the slight knocking/rattle right behind the reed block was the same as at the beginning of this whole issue. Completely frustrated. Want to pull the power head and refurbish (glass bead most likely) the exhaust adapter plates. Regasket and try again. My opinion is that there is a connection between the power head, and or exhaust plate gaskets failing and the slight knock or rattle. And no there has been no sign of water in the two lower pistons. All suggestions and comments appreciated.
