cooling on a 1973 65 horse model 65esl73

[loquito]

My very first baot trip in the family's very first boat ended with an overheated outboard and the kids laughing uncontrolably while I paddled twards shore.

So I am going to look into the water pump impeler etc. It seems that the water is having a hard time getting up into the motor. If I put the hose on the end of the intake tube(lower unit removed) it will travel up to where the thermastat is but it seems to take a lot of preasure to get the water to the top of the motor. Then even with the thermastat and Preasure releif valves removed i get no water returning throught the water out area.

Any advise on things to check for.

My Service manual shows a water in as well as a water out spot, but no mention of a pee hole. Is there on on this motor?

Thanks you guys.
Steven

 

[WillyBWright]

Re: cooling on a 1973 65 horse model 65esl73

No pee hole. Look for water spraying out of the exhaust relief holes on the back a few inches below the hood. There's apparently a blockage in the system. I'm going to assume that the impeller is in pieces and one or more lodged upstream. Whenever I do a water pump where there are pieces of the impeller missing, I make sure I find them. At least the ones big enough to cause a problem. Anything smaller than a pea should pass through. Anything bigger will get stuck. I also backflush them through the thermostat and bypass passages with the gearcase off which it sounds like you are doing. That usually pushes any blockages out. You might end up taking the powerhead off and finding a piece of old impeller right where the water enters the base of the powerhead that is in cockeyed and won't flush out. Rare, but happens. Alternating forward and backward flushing usually dislodges them.

 

[loquito]

Re: cooling on a 1973 65 horse model 65esl73

Can you tell me more about the exhaust relief valves. I found them on the Service manual. And I know on the motor where they are. But I didn't know they were valves, water should come out of them?
My impeller was in one piece but I am starting to look for blockage.