77 mercury115 loss power

7

77Glastron

Recruit
Joined
Aug 31, 2008
Messages
1
i hvae a 77 mercury 1150 115 hp that has no power in the water. if i tilt the motor up and get the prop out the water it revs up but as soon as it gets in water it drops to an idle. at WOT it is barley moving on the water. i was pulling a tube at wot when it started this and i removed the hood and the screws for the ignition where vibrated lose and backed out! any ideas what to look for? could the ignition be bad only under a load???
 
Yepblaze

Yepblaze

Lieutenant Commander
Joined
Jun 1, 2001
Messages
1,686
Re: 77 mercury115 loss power

Oh, it could be so many things.

I would suggest a compression test to assure that any repairs performed now aren't in vain.

Did you try pumping the fuel line bulb while it's losing power? (It's an easy fuel pump diagnostic test)

Yes, an ignition can operate at reduced capacity.

If some screws fell out, maybe replacing them will help.
 
C

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
29,035
Re: 77 mercury115 loss power

After you do the compression test to assure the motor has good even compression, you need to check the idle pickup timing, max timing and carb synch to the timing. If your timing has changed, and you do not properly reset it, the motor could suffer significant damage.
 
Yepblaze

Yepblaze

Lieutenant Commander
Joined
Jun 1, 2001
Messages
1,686
Re: 77 mercury115 loss power

Oh, those screws. Yea, that could do it.
 
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