water flow 1980 75hp

[CBINMN]

J75trlcsa

I finished complete rebuild of powerhead, replaced water pump,rebuilt carbs & replaced gas lines, and put all back together. It runs great but the tell tale stream gets weaker and hotter the longer it runs. One time to the point I couldn't hold my hand in the stream. I immediately shut it down. I removed lower unit and thermostat cover and checked water pump install , ran hose up water tube and back down with good flow (I think I had poppets in backwards- long side to spring). Figuring I was good I started it again ( on muffs) the stream started out a lot stronger then slowly weakened again. There was a lot of water coming out where mid section mounts to the pivot just above cavitation plate and a stream to the front where lower and mid connect. Also exhaust is coming from the holes at the rear of lower unit just above the cavitation plate . From the diagrams in the manual it looks like water should be exiting there. Any suggestions?

Chris

 

[HighTrim]

Re: water flow 1980 75hp

You did not mention if you replaced the thermostat(s)?

 

[CBINMN]

Re: water flow 1980 75hp

sorry, yes replaced thermostat and poppet valves and grommets

 

[HighTrim]

Re: water flow 1980 75hp

It sounds like you have a grommet restricting water flow, either at the impeller housing or at the top of the water line. Just a guess though.

 

[CBINMN]

Re: water flow 1980 75hp

I checked it at water pump,grommet is between pump and plastic sleeve then tube goes into plastic sleeve. How much should water tube move with lower off if at all? It did have some movement.I think I will go drop l/u again and confirm. I hope it's not the topof tube cause that means pulling powerhead again.

Thanks,
Chris

 

[CBINMN]

Re: water flow 1980 75hp

Ok, removed l/u put hose on water tube with thermo and poppets in place. water was going from telltale nicely, but water leaving motor only coming back into mid section. Shouldn't some come out of the area to rear of exhaust also which would have water coming out of the l/u just above cav plate above prop? or does it just come out there after thermo opens?

Chris

 

[CBINMN]

Re: water flow 1980 75hp

Went to do some more checks. Took poppets out and ran water through tube and had great flow, I believe I got some gasket sealer on poppets making them harder to open. put poppets back in (with a little grease to keep em from sticking) and ran water up tube and flow was good. Will also get a large barrel to put motor in to test after its done snowing again.