Posted By: HappyNest
1999 Mercury Force 120 - Loss of Top end speed - 06/11/22 09:09 PM
Hi everyone, I hope your all having a nice weekend.
I have a 1999 Mercury Force 120 that has dropped from a top end speed about 45 MPH to about 40 MPH. The prop is in good shape and the boat hull is clean. The Motor runs and idles good but stops at about 40 MPH and 3200 RPM. I have gone through the fuel system and it is clean including taking samples of the fuel hose. I replaced the reeds, Compression is about 108 on all cylinders. I found a visually weak spark on #2 cylinder so I swapped modules around but it remained weak on #2 cylinder.
I took ohm readings on the Stator Green/White to White/Green is 724k Ohms. I have ordered a DVA to check the output voltage.
I checked the trigger Black/White to
C1 - Purple 796k ohms,
C2 - White 4.15m ohms,
C3 - Brown 850k ohms and
C4 - Blue 628k ohms.
I found a paper at www.outboardignitions.com that indicates the Stator should be 500-700 ohms and 180v. The trigger is indicated that it should be 800-1100 ohms.
Any thoughts on things to try or what might be wrong before I go purchase some parts?
I have a 1999 Mercury Force 120 that has dropped from a top end speed about 45 MPH to about 40 MPH. The prop is in good shape and the boat hull is clean. The Motor runs and idles good but stops at about 40 MPH and 3200 RPM. I have gone through the fuel system and it is clean including taking samples of the fuel hose. I replaced the reeds, Compression is about 108 on all cylinders. I found a visually weak spark on #2 cylinder so I swapped modules around but it remained weak on #2 cylinder.
I took ohm readings on the Stator Green/White to White/Green is 724k Ohms. I have ordered a DVA to check the output voltage.
I checked the trigger Black/White to
C1 - Purple 796k ohms,
C2 - White 4.15m ohms,
C3 - Brown 850k ohms and
C4 - Blue 628k ohms.
I found a paper at www.outboardignitions.com that indicates the Stator should be 500-700 ohms and 180v. The trigger is indicated that it should be 800-1100 ohms.
Any thoughts on things to try or what might be wrong before I go purchase some parts?