89 Force 85 severly under powered

G

greezzmunkei

Recruit
Joined
Jun 2, 2005
Messages
1
i got the boat sight unseen and had to rewire it, the engine has 110 psi compression or better between all 3 cylinders and will max out at full throttle at 3000 RPM the prop that came with the engine was a 14x21 so i changed it to a 13&3/4x15 with no improvement...the boat will not plane out and i 'm at the end of my rope. the engine does not miss and runs great it's just weak or has the wrong prop. i don't know which. any help would be apreciated. the motor is mounted on a 19' Renken cuddy cabin..Thanx
 
D

DJ

Guest
Re: 89 Force 85 severly under powered

That's a heavy boat. The Force 85 was a never a stellar performer to begin with.<br /><br />Are you sure it's firing on all three cylinders?
 
T

t.martin

Petty Officer 2nd Class
Joined
Apr 27, 2005
Messages
121
Re: 89 Force 85 severly under powered

Do you have tilt/trim or do you adjust with a pin? If you have a pin have you tried higher settings?
 
B

bnk999

Petty Officer 2nd Class
Joined
Mar 20, 2005
Messages
137
Re: 89 Force 85 severly under powered

Yes that is a heavy boat- Pull plugs and make sure they all look the same -- check for *GOOD* spark on all three-- have you tried to decarbonize the motor with seafoam?
 
D

Docdoc

Petty Officer 2nd Class
Joined
Mar 3, 2005
Messages
196
Re: 89 Force 85 severly under powered

When you pull the plugs, check to see if one or more of the plugs look clean compared to the others. That's usually a good sign that it's not firing. Unlike automotive engines, these motors will start and run smoothly on even one cylinder, however, when put under load, they just will not perform.
 
S

sniperjdp

Cadet
Joined
Sep 11, 2004
Messages
7
Re: 89 Force 85 severly under powered

If one of the two ignition modules is bad that will cause your problem, IE low RPM. One unit fires two spark plugs, the second one fires the third plug. I had the same problem on my 16 foot Bayliner Capri, it ran like crap, replaced the ignition units and now I get 40MPH out of it!! The local boat places wanted over $350.00 for each "black" ignition module, I ended up getting NEW units from the manufacture, Standard Magneto Co. for $80.00 each. Go here, http://standardmagneto.com/Parts.html they also sell/make stators, etc, GREAT pricing!!
 
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