94-96? Johnson 60HP 2-stroke overheating - order to test/fix?

beniop

Cadet
Joined
Aug 1, 2009
Messages
19
It never fails; for every one good ride the next will end in suck.

After 5 minutes of running at even mid-throttle the overheat alarm comes on and it seems that there is more gray-white smoke than I've seen (we've used the boat maybe a dozen times).

Facts:
  • Compression tests 130ish on all 3 cylinders
  • New plugs
  • Removed & cleaned the carbs about 4 or 5 trips ago with the supervision of a bona fide outboard mechanic
  • We are running an above-deck tank which I just installed because I wasn't getting any fuel from the in-deck anymore.
  • Telltale is strong and warm.

What are the parts and procedures that I should test/replace? My searches here indicate that the thermostat and water pump should be replaced given that I have no knowledge of the service this motor had from the previous owner. I suppose I need to check the plugs to make sure they aren't getting fouled, and I'm pulling it out of the water today to run it on

My biggest question is whether poor lubrication could be causing overheat or if it is likely just the cooling system. A few runs ago we rocked through some oyster beds and I'm wondering if there was some crud sucked up that has been collecting other crud in the water system.

As always, any thoughts/help appreciated.

Boat is a 95 Key West flats boat currently running in deep salt water tidal creeks in SC, FWIW.
 

beniop

Cadet
Joined
Aug 1, 2009
Messages
19
A little more info

A little more info

As my wife brought the boat the 1/2 mile to the landing from the dock, i asked her to open the vent (oops) on the gas tank, and it seemed that solved the issue of the alarm. Perhaps it was a fuel constriction issue.

A couple other things:
  • Telltale stream cycles through hot and less hot every few seconds
  • Motor does have a very slight oilyness to the water coming out of the exhaust at the prop... normal?
  • Ran the motor for several minutes @ mid-throttle on the hose, did fine.
  • Motor is a 95 Johnson 60TLEOC
 
Last edited:

Solittle

Fleet Admiral
Joined
Apr 28, 2002
Messages
7,518
Re: A little more info

Re: A little more info

Fuel construction would not come into play in an overheat situation. My suggestion is to replace the water pump and t-stat before you start the engine again. If you don't you risk facing a rebuild.
 

Daviet

Fleet Admiral
Joined
Sep 24, 2008
Messages
8,958
Re: 94-96? Johnson 60HP 2-stroke overheating - order to test/fix?

Running an engine on a hose will mask a bad water pump, the water pressure from the hose will bypass a bad water pump.
 
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