1987 mercury 115 I6 question

Roger S.

Recruit
Joined
Jul 20, 2016
Messages
5
Hi, I have a Cajun Fish n Ski with a tower of power I6 115 on it. Motor was flooding out bad, found the top carb float was bad and replaced it, now it runs great except for 1 thing. Well, it has an occasional hiccup, but I guess thats to be expected from a 30 year old motor. My issue now is, when I put the boat back on the trailer and try to power up the bumper boards to the front of the trailer, it just won't. Bogs down, like it has no power. If I keep trying, it will die. I have no trouble getting on plane and running about 45 MPH at 4800 RPM. Start fine, except for the normal cold naturedness of these motors. Any ideas?

Oh, just remembered something else I wanted to ask. I have a good tell tale stream of cooling water, Pressure gage shows about 1 PSI at idle and 6 at WOT. But I noticed there is also some water spitting out right below the motor, where the little band cover is that has the horsepower sticker on it. Is this normal?
 
Last edited:

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,073
The two square holes high on the midsection are exhaust relief. The can and do spit water, especially at idle.

If your top carb was faulty, I expect your other carbs need attention. It makes sense to remove, clean and rebuild all carbs. Use new gaskets, floats and inlet needle and seats.

The difference between no power when trailering the boat and the power you have when cruising is the trim of the boat and motor. Much higher when trailering. Try trimming the motor up to put her on the trailer.
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
13,631
Those engines do get grumpy when you try to run them tilted up as in shallow water or power loading on to trailer. Your water pressure isn't too bad, the inlines never get much over 7 with a new water pump. If you ever do see higher pressure, it means the engine is starved for water and what you are reading is steam pressure.
 

Roger S.

Recruit
Joined
Jul 20, 2016
Messages
5
Thanks guys. So I should experiment some with tilt while loading? I'll give that a shot.
 

jimmbo

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Joined
May 24, 2004
Messages
13,631
Just be careful not to lower it too much, or you will be posting in the Propeller Forum
 
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