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93 Johnson 60hp Overheat

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jeff_32

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I have a 93 Johnson 60hp that is overheating. I've replaced the thermostat and the powerhead to exhaust gasket. If I remove the thermostat it runs cool but not the fix I want.

Any suggestions?
 
Is thermostat opening at proper temp. Can be tested in a pot of water while suspended. Have you tested the compression on heads yet?water droplets on plugs,steamed cleaned plugs??
 
Is telltale stream hot to touch? Can hand be placed on head for a six second count? Your thread says engine runs cool without thermostat but its overheating which one is it? Does engine have a strong telltale flow? What is the warmed up temp. on engine? Infrared temp gun will work on heads,20$ at harbor freight.
 
johnnygjr said:
Is telltale stream hot to touch? Can hand be placed on head for a six second count? Your thread says engine runs cool without thermostat but its overheating which one is it? Does engine have a strong telltale flow? What is the warmed up temp. on engine? Infrared temp gun will work on heads,20$ at harbor freight.
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The telltale stream is hot to the touch and is very strong pressure. The engine runs 105 - 107 degrees with the thermostat and other parts removed from the thermostat housing. With a new thermostat put in the housing it runs 160ish...too hot.

Looks to me that the problem is with the thermostat or springs at this point. Before I put the new thermostat in it would continue to get hotter than the 160 degree point.

Should I replace the spring and diaphragm?
 
Does the telltale hose come off the side of the block or off the top ?----------Service bulletin from 1994 indicates this should be done.
 
Yes it comes off the top of the block. I removed the impeller and it looks fine. Flushed the system and didn't see anything come out but water. Just seems like the thermostat isn't opening all the way and it is a new one.
 
Where are you running motor,on muffs,in water, on lake or bay, in a drum? salt or fresh water history? IF salt use ,Have you tried to desalt engine . Has compression test been done yet? Was water pump housing sealed when it was installed?
 
Running it in a drum and using a temp gun to monitor engine temp. All keeps coming back to the thermostat not letting water flow, but I've replaced it once with better results than before but still not cooling like it should. Originally the temp would constant climb to 180. Removed thermostat and would run 105 - 106. Installed new thermostat and runs at 160.
 
How long are you running it in a drum? you will start to recirculate water that has been circulated once if telltale flow is redirected into drum,warmer& warmer as time goes on!! Do you see where i going with this? need to supply new cooler water continuously into drum,hope this helps
 
You've been describing a failing water pump assembly regardless of how it looks. Replace the assembly, not just the impeller.
 
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