This is a new to me outboard. I am lost on what to do next. Engine runs fine at idle, decent water flow, and does not overheat. However, after running it 1/2-full speed engine overheats after only a few minutes. I have sanded the head to .002 and replaced the head gasket. The impeller is in one piece but vanes are bent so I have a new one one the way as well as an impeller plate and a new grommet. The impeller plate did not have the gasket maker on the bottom when I removed it. Sealoc manual recommends it. I connected the lower unit to a drill and water flow was no problem through the housing with the current impeller. I have run both compressed air and water through the entire outboard starting at the water pick up tube. Had water coming from the exhaust as expected and increased with water pressure. Air could be felt coming out of exhaust with compressed air. I removed the whole motor off of the lower unit. I found that the gasket between the powerhead and the lower unit was falling apart except where the water flows to the power head. The exhaust was broken in two at the top and must be replaced. I ran compressed air through the powerhead from both the intake and outlet ports for the water. I could feel a nice blast of air both ways. Cannot figure out why it’s overheating. Trying to decide if I should continue to put a bit of money into it or not. It runs well and sounds good until it overheats. The cylinders looked great. No scoring. Seems like a motor worth saving. It came with a 16’ Starcraft aluminum boat and trailer that I am going to use for duck hunting, as well as, some fishing and crabbing.
