75HP oil consumption

Nick on the Bad Habit

Petty Officer 2nd Class
Joined
Dec 11, 2004
Messages
144
Excessive oil consumption
Here's the deal. I have owned this 20 ft 1997 Valco Bayrunner for a few years and now have 2200hrs on it. I've been reading about performance issues with the 75 HP outboard that were diagnosed back to the thermostat not closing, and allowing the motor to run cold. I pulled out my t-stat to find indeed the t-stat was wide open all the time. I changed out the t-stat, and the engine ran a lot smoother and no longer stumbled when the throttled up quickly. I was very glad for the improvement in performance.
Whoever now the engine burns oil like crazy, 3/4 of a quart in thirty five miles at 4000RPM and about 18knots. I can only surmise that the rings never ran at the normal temperature and now will not seat properly.
Any ides as to what is wrong, and suggest a fix, other that the obvious ring job needed?
I did a compression test this afternoon and got 170 to 185 PSI across all cylinders
Nick
 
Last edited:

hondon

Lieutenant Commander
Joined
Jun 11, 2001
Messages
1,922
Re: 75HP oil consumption

Is that 4000 at wide open ,and have you always been like that?
 

Nick on the Bad Habit

Petty Officer 2nd Class
Joined
Dec 11, 2004
Messages
144
Re: 75HP oil consumption

4000 RPM is my normal cruising speed (18 Knots). I can get about 5200 RPM at WOT(30 knots).
 
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