Back to the drawing board. Changed impeller and STILL OVERHEATING. '87 90HP

[bang4dabuck]

Tomorrow I'll pull T-stats and see if she runs cool without them. Should I pull the VALVES too ??? Any other things to look at while I got all that apart ? My father who has been helping me here and there and is not a mechanic but is a pretty smart guy, believes it is a water exhaust issue. i.e. something is interfering with the water getting out. I HAVE CHANGED THE IMPELLER,T-STATS AND VALVES AND WATER DEFLECTERS. My telltale is spraying good. It is only running hot on the STARBOARD SIDE. We disconnected the starboard hose that goes to the t-stat housing and it seemed to be pushing the water good FWIW.

 

[Daviet]

Re: Back to the drawing board. Changed impeller and STILL OVERHEATING. '87 90HP

A good tell-tale indicates that the pump is working. Go ahead and remove the stats and valves and see what happens. A defective head gasket can pressurize the cooling system and not allow water to circulate, do the plugs show any signs of water on them?

 

[bernd64]

Re: Back to the drawing board. Changed impeller and STILL OVERHEATING. '87 90HP

i bet you have a block in the head see if you can back flush the motor with out the L/U on it in a bucket so you see if you have something in the motor

 

[boobie]

Re: Back to the drawing board. Changed impeller and STILL OVERHEATING. '87 90HP

Does it overheat with the hose pulled off of the starboard side head??

 

[bang4dabuck]

Re: Back to the drawing board. Changed impeller and STILL OVERHEATING. '87 90HP

The head gaskets are virtually new. I changed them this winter when I changed the deflectors. I got to admit, I think I got a little overzealous and applied gasket sealer to both head gaskets.

I will check the plugs.

I will disconnect hose from t-stat housing and run. If it still runs hot I guess there will be no need to pull t-stats and I should pull that one head out and clean up thoroughly. Can I re-use that head gasket ?

If instead it runs cool I will pull t-stats and go from there. Sound like a plan ?

 

[boobie]

Re: Back to the drawing board. Changed impeller and STILL OVERHEATING. '87 90HP

Yes, sounds like a plan. It's not recommended to use head gaskets over but I've done it in a pinch when I didn't have one. Put OMC gasket sealing compond on it before installing.

 

[bang4dabuck]

Re: Back to the drawing board. Changed impeller and STILL OVERHEATING. '87 90HP

Connected a long piece of hose on OUT SPOUT on starboard head i.e. to confirm hot water exit was not the problem. It ran just as HOT !!!

Checked all 4 plugs and all were wet, seems like fuel.

Checked compression and 120ish ALL AROUND.

Time to take head off ???

And from there what do I look to do on head ? On BLOCK ?

 

[bang4dabuck]

Re: Back to the drawing board. Changed impeller and STILL OVERHEATING. '87 90HP

BTW - I will put in a new head gasket even if I a week if ato drive 20 miles each way or wait a week if I order online.

 

[bang4dabuck]

Re: Back to the drawing board. Changed impeller and STILL OVERHEATING. '87 90HP

How about using some SALT AWAY or something like that (CLR I was thinking) ?

I saw on the parts breakdown a CHECK VALVE but it is confusing. Looks like it is in place of a deflector. I don't remember coming across this when I had heads off. Part numbers 10. Are they optional ?

http://www.boats.net/parts/search/BRP/EVINRUDE/1987/E90TLCUR/CYLINDER & CRANKCASE/parts.html