9.8 not cooling properly??

[cmal]

Hi, I've got a 9.8 Merc from what I can tell its a 1983. Ser#7200128. It pumps water but not a steady stream in neutral if I put it in gear and its pretty steady with decent flow.I checked the impeller it's like new. Blew out all the lines and this motor doesn't have a thermostat. I left the motor running for 10 mins in a Barrel in gear it didnt overheat but the water coming out of the tell tale is very hot right from start up I can barely hold my hand under it for a second or two. I'm assuming this is not normal operation for these mercs? I know my Johnson with a thermostat pisses Luke warm water at best and is a steady flow weather it's in neutral or hin gear. Any ideas out there? Thanks

 

[tomhath]

Definitely should not be hot water coming out. Did you take the water pump completely apart? I've found the remains of a damaged impeller inside a pump with a good impeller (I guess the previous owner didn't bother to look for the missing fins).

 

[tomhath]

Definitely should not be hot water coming out. Did you take the water pump completely apart? I've found the remains of a damaged impeller inside a pump with a good impeller (I guess the previous owner didn't bother to look for the missing fins).

 

[cmal]

I did take the pump apart everything looked good inside. I might just change the impeller for the few dollars it will cost but I have a feeling it won't change anything.. To me it is behaving like a sticky thermostat but it doesn't have one.......

 

[racerone]

At the top of the water tube there is a plastic washer.-------This washer melts on severe overheat and then blocks water flow to the engine.------Powerhead needs to be removed to check this.--Not hard to do !

 

[cmal]

I did pull the powerhead and sure enough it was the washer melted with just a pin hole in it... Changed that replaced the base gasket put it back together and for the hell of it changed impeller.. Started first pull and has a steady stream of cool water coming out. I have a bit of exhaust and a must of water coming out of the back of the motor is this normal

 

[tomhath]

There's an exhaust relief to reduce back pressure when starting or idling. It will spray a tiny bit of water. Sounds like everything is good now.

 

[cmal]

Yes it runs like a top..thanks for the input