boat not plaining off?

dodgefate

Cadet
Joined
Apr 27, 2009
Messages
19
HI everybody im new here and new to boating so please bear with me if I use the wrong teminoligy. I was recently given a boat. I fixed a hole in it and put a new prop on it and took it out for a test drive. The prop I put on was the same as the one that came off, dont know the pitch or anything... the problem I am having is when I start the boat on land ( With earmuffs) the thing runs great. It sounds like it gets to about 5500 rps or so (No tac). When I take it in the watter the frint end comes up pretty high and the motor ony sounds like its putting out 2500 rpm's. If you throw some weight in the front the boat picks up speed. I set the engin on the lowest setting and it seemd to help a little but not much. The boat was sitting for 2 year and maintined pretty well before it sat. Im going to change out the plugs today see if it helps. Also there was three wires inside the engin that were broken. Two went to the stator and one went to a sensor under the stator that attches on the crnak. I replaced the three wires. The boat is a 1970 winner modified v hull 18foot and the engin is a 1986 75 hp merc 4 cyl. There was about 3 gallons of gass in the tank when i got it, it was starting to turn so i added 15 gallons of fresh hightest and oil. I see alot of people on here telling others to pump the primer when at full speed. Havent done this yet just wanted to know the logic behind it..... any sugestions would be greatley appricated.
 

NCCamper

Cadet
Joined
Feb 3, 2009
Messages
28
Re: boat not plaining off?

Did you really run it up to 5500 RPM on the muffs?

NCC
 

dodgefate

Cadet
Joined
Apr 27, 2009
Messages
19
Re: boat not plaining off?

I taki it that is a bad thing? Im just estimating here but it sounded about that, only brought it up then down.... Used to be a car mecanic for 7 years so just estimating off of what i know
 

NCCamper

Cadet
Joined
Feb 3, 2009
Messages
28
Re: boat not plaining off?

Well, maybe I'm wrong; maybe it's different for outboard motors; but everything I've ever heard about running on muffs, was to never go over 1200 RPM. To do so may cause a collapse of the water hose from the suction, and therefore a loss of water from the source, and then...well, I hope I am wrong. Does the boat have a temp gauge? I am surprised no one else chimed in, though.

NCC
 

dodgefate

Cadet
Joined
Apr 27, 2009
Messages
19
Re: boat not plaining off?

dident hold it there long just reved it up and down..... stiill shot out a nice stream of water the whole time
 

new boat guy

Seaman
Joined
Mar 31, 2009
Messages
56
Re: boat not plaining off?

how long was it up that high? if under 30s or so i think you'll be okay
 

dodgefate

Cadet
Joined
Apr 27, 2009
Messages
19
Re: boat not plaining off?

just a quick rev, maby a halfa second or so nothing too bad
 

dodgefate

Cadet
Joined
Apr 27, 2009
Messages
19
Re: boat not plaining off?

update prop is a 13.25 by 17 pitch..... boat weighs aprox. 2000 lbs
 

dodgefate

Cadet
Joined
Apr 27, 2009
Messages
19
Re: boat not plaining off?

fixed it turns out the ground wire to the #2 coil was breaking and not making contact
 
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