Question on Merc outboard thermostat & fuel flow

tmitchell5188

Seaman
Joined
Mar 17, 2008
Messages
73
I have a 25' Trophy with twin 1996 175 HP outboards 2 strokes, one being a counter rotation engine. I have a Flow Scan fuel flow meter system, and I noticed that my port (counter rotation) engine uses more fuel than my starboard engine.

How much you ask? Well, a lot. By a lot I mean I burn 12 GPH on the starboard, and 18 GPH on the port! Well, I was out today, and we went out 15 miles to fish. I've never gone past 6-7 miles before. I noticed on my way in, that after about 12 miles, my fuel flow meter on the port engine had dropped from 18 GPH to about 13-14 GPH.

Could it be that the thermostat finally opened, and the engine was running too rich, and then leaned out? I'll keep an eye on this tomorrow, but I think this may be worth putting a new stat on the port engine. FYI, these are the original stat's on the OB's.
 

tmitchell5188

Seaman
Joined
Mar 17, 2008
Messages
73
Re: Question on Merc outboard thermostat & fuel flow

FYI, I replaced the impellers last year, the boat has been used in fresh water only, and there is the tell tale P stream out the back, and the OB's are not over heating.
 
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