125 force missing not opening up past 4000 RPM

[y-knot]

I have twin 125 HP force motors(1989) on a 23' trophy. One runs and opens up to somewhere past 5000 RPM the other tops out at 4000.<br /><br />I checked the compression (fine) and all 4 cylinders are getting a spark. It also shakes at low rpms (700 to 1700) and seems to stop as it spins faster (if you touch the motor at 4000 it is shaking a little more than the good one.) Finally, when I back off from full throttle, it comes down faster and doesnt seem to climb in RPMS as fast at the other.<br /><br />I've read most of the other force posts and appreciate all the information everyone shares. <br /><br />Look forward to the help.

 

[clanton]

Re: 125 force missing not opening up past 4000 RPM

What is fine compression? Use timing light as tester connect timing light, boat in water, run engine full throttle in farward gear, light should be brite and even, check each cylinder. The misfiring cylinders will show on timing light( you have to look at light). Takes two people, dont fall out of boat. If light brite and and even at all rpms you have fuel problem, dont forget to check the exhaust hose, and sparkplug wires.

 

[sony2001]

Re: 125 force missing not opening up past 4000 RPM

y-knot, I'm quit sure you are running on three cylinders. Its a classic case except the other motor is dragging your revs up to 4K instead of staying at 3K. Check your CD unit.

 

[y-knot]

Re: 125 force missing not opening up past 4000 RPM

Sorry for the delay in responding, I was away for a few days. <br /><br />I will try the timing light on all four cylinders at high speed. That will prove if I'm getting spark consistently. <br /><br />I should have her out tomorrow.

 

[y-knot]

Re: 125 force missing not opening up past 4000 RPM

Took her out today, but didn't have a first mate to check the engine with a timing light. I did however pull the plugs and found three of the four wet (brown oil stains) #3 was the exception, it was clean. This engine has a new stator, a new CD box and a new coil on this cylinder. She is getting a spark on that cylinder. I don't have a DVA tester to check the high voltage output, but could the trigger switch be shorting at the high voltages? When I replaced the stator, the trigger switch had a score on it(Like something dragged across the face) and one magnet (I believe-looks like a church with a rounded steeple) had half of the brown covering missing.<br /><br />Could this be shorting at the high end?<br /><br />Thanks for the help.