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1969 Johnson 9.5hp thermostat?

jim18611865

Regular Contributor
Just boat tested a very nice condition 69 9.5. Boat ran very well (12 mph w/ 2 people on a 12' alum and 6 gal fuel) and even idled well and started on the second pull despite the low compression. 50 psi on both cyl.

Water output is quite massive out the exhaust relief hose whether the engine is hot or cold. It lessens with lower rpms and really pumps at high rpms.

Does this sound like a stuck open thermostat?
According to the paint on the powerhead I would guess it has never been changed. Should I change it?
Only problem I could complain about is it seemed to be about 7-8 hp and not a 9.5. But I am comparing to a 89' 6hp on the same boat.

Thanks all as usual.
 
Re: 69 Johnson 9.5 thermostat?

That motor should move the boat at at least 15mph...Slipping or incorrect Prop????...Wrong motor angle??? Exhaust leak under the cover(common on these motors)...try running with the cover removed
 
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