1968 1.5 HP Mate Model #1802S Engine Running Hot!

Last year I was trolling for lakers in the fall and my 1.5 HP Mate started running hot. I have not replaced the water pump impeller since I have owned it (3 years) and it probably has gone bad as it might be the original. It does start up but I don't want to run it for long as I know it could ruin something. I love this engine as it gets to the right speed that fish like to hit on. I plan to go fishing soon but I have put off taking the motor apart as I am not that good at all the mechanicals and do not want to break anything or lose any parts. What would be the protocol for seeing if that rubber impeller is bad or not. There are 2 screws above the propeller that I have been eyeing that I believe would take the whole bottom assembly off but I guess I don't know for sure. Hopefully I can get this accomplished. Please help.

The lower unit retaining bolts are pretty obvious on that unit, only two of them. If either of them seem to be frozen, use a hand held propane torch to help loosen them. The water pump sits directly on top of the lower unit..... no rocket science mentality required. Break out your wrench and go at it.

Thank you Joe, I appreciate your response. I believe I will have some time tonight and will let you know how things work out. It will be nice to get on the water. What a long winter it has been.