1968 Johnson 9.5 how hot is too hot?

meyerboy

Petty Officer 2nd Class
Joined
Dec 10, 2009
Messages
100
I just adopted a really nice little 1968 9.5 from the outboard Gods. This one came from a duck hunter that no longer hunts.

It is clean enough to eat off under the cowl, and started on the second pull, though it has been sitting for years in a shed.

Before I put it in the tank, I took the lower end down to the impeller, and it looked as good as the rest of the motor, so I changed the gear lube, and started her right up.

The water from the pump is a nice strong flow, but it is hotter than most of my other motors. You can put your hands under the stream, and it won't burn you, but it does steam at little, and just seems too hot.

While I had the lower end off, I blew air through the tube, and no stuff came out at all.

I do have a mix of salt-away in my tank, and she ran for half an hour in that with no change.

any insight ????
 

wilde1j

Vice Admiral
Joined
Apr 15, 2002
Messages
5,964
Re: 1968 Johnson 9.5 how hot is too hot?

If you can put your fingers on the cylinder head w/o getting burned, it's not overheating. Most outboards run between 130 and 150? F, the temperature of moderately hot water from your faucet.
 

ezeke

Supreme Mariner
Joined
Sep 19, 2003
Messages
12,532
Re: 1968 Johnson 9.5 how hot is too hot?

The thermostats are easily replaced.

You still get the water out of the exhaust relief even when nothing is flowing through the cooling passages of the engine, so it pays to test the thermostat.

Also, be sure that you are using the recommended plug, Champion J4C, or at least nothing hotter than a Champion J6C.
 
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