1990 15hp Cooling problem

[samo_ott]

Ok, I'm back looking at my friends (virtually new) 15hp. It barely spits out any water out the pee hole at all speeds. And the water is very hot and steam is also coming out with it. The exhaust housing and thermostat housing are also too hot to touch, so to me it seems like a classic impeller/water pump problem, but is there anything else on this new fangled engine that it could be? Also how hard is it to drop the lower unit on it if that's the prob? Where does one disconnect the shifter? It's an electric and a long shaft.

 

[iwombat]

Re: 1990 15hp Cooling problem

The shift rod will disconnect at the top of the extension via a coupler. You'll then need to take off the extension to service the water pump. Convenient, eh? Anyway, nothing fancy there. Thermostat is under the round dealy-doober on the head.

Steam out the hole indicates an air leak to me. Have you done a compression check on this yet to see if you've got a head or exhaust gasket problem?

Edit: Six bolts to get the LU off, then six more to get the extension off. Nothing hidden.

 

[samo_ott]

Re: 1990 15hp Cooling problem

I figured the steam was just the superheated water coming out... but maybe a head gasket issue... hmmm... it had ok power from what I heard... but I'll check the compression, that's an easy hit.

Do these models have any history of clogging water passages? (it's a fresh water motor also) or is it a safe bet that it's probably the impeller/pump?

 

[iwombat]

Re: 1990 15hp Cooling problem

Tell tales clog all the time. Run a wire or some weed eater cord up the spout and check it out. The heads and thermo were hot, so I figured you had a real actual problem on your hands.

Water passages - maybe if he's been running in a lot of mud or weeds. Be sure to clean out the intake screen under the pump in that case.

 

[reload]

Re: 1990 15hp Cooling problem

My 9.9 will clog water passages sometimes. I little toying with it will open them up. Just can't let them dry.

 

[samo_ott]

Re: 1990 15hp Cooling problem

WHere do the 9.9 passages clog up? And how much work to unclog?

 

[samo_ott]

Re: 1990 15hp Cooling problem

OK, here's the update. And I know the answer but am asking anyway.

Got it out of the water and in the test tank. Just did compression test on it. And it's not good. 58lbs in the top and 78 lbs in the bottom. To me this seems toast. Coupled with the dark tinge on the thermostat housing and head it looks like it was severly overheated and hence why it was running like crap for the owner.

What are my options? Retorque the head? I doubt it will help. Head gasket? doubt it also but maybe. Rebuild? Probably. Ideas? Comments? thx.

 

[reload]

Re: 1990 15hp Cooling problem

Pull the head and check it, could be warped. This is a common occurance with overheating.

 

[wbeaton]

Re: 1990 15hp Cooling problem

Pop the head and the exhaust cover and look at the cylinder walls, rings and cooling passages just before the pee hole tube. I think you have a parts motor on your hands. At least a visual inspection will tell you if its even worth rebuilding.

 

[mikesea]

Re: 1990 15hp Cooling problem

A very common problenm for the 9.9 and 15 is the cllapsing of the grommet on top of the water tube where it terminates under the powerhead,over time the grommet swells from salt,corrision that may happen due to the differance of metals at that point.The way to fix it right is removal of the P/h and lower unit,and replacing the 50 cent grommet and p/h gasket.A trick Ive done often ,take a wire clothes hanger ,get a strait piece long enough to reach up into the tube to grommet,smash one end til it makes a speah head and sharpen,using a drill,put onthe end in chuck and kida router roter the hole larger,dont bite too much off at once,it does work SOMETIMES,as for the comp,differance,I think the head warped,get a piece of marble,etc,take some 80 grit emery,and make a few passes on the sealing surface of the head and see what you got,you can probably get it true,change the gasket and do new comp.test,be sure to torque slowly and evenly,I dont have the lbs.right now,you might be able to cheat a bit and save on the cost of a head gasket
TEMPORARLY to see if comp comes back using gasket sealer,but I wouldnt run it like that,you might want to try the test first