Ok...got to thinking... the score marks on the inside of the flywheel are even all the way around... no mark is deeper than any other mark...and the groove is the same depth all around. If the crankshaft snout was bent so there was runout then one side of the marks on the flywheel would be deeper than the opposite side from hi-low flutter. That's not the case here. So then I put an indicator on the snout, put the engine in gear and using the prop turned the engine a few revolutions. No detectable runout on the stub.
Only one of the coils has rub marks on it. The spark coil closest to the boat hull. (There are 3 spark coils, 1 in the front of the engine and 2 that are 180 degrees from the first one at the back of the engine). Is it possible that the front coil is somehow high?? Is that even possible?
Although the groove and marks in the flywheel appear to be bright metal, it's possible that this damage is old. Upon inspecting the flywheel I can see that a few of the magnets have been re-glued, so there was obviously a problem some time in the past. Only thing I can think of to do next is put Dykem on the top of the coil, remount the flywheel and spin the engine a few times, then take the flywheel back off and see if the Dykem was rubbed off. If it was then I know that it's hitting. If it's not then maybe this is all from the PO and it's a non issue. I'm totally stumped on this one. Aside from the gumming issue the engine runs strong. I just want to keep it that way.
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1987 V20 w/1987 150HP Yamaha on a Shoreland'r Trailer
1978 16.5 Airslot w/1996 120HP Force on a Four Winns trailer
1996 V21 w/1993 200HP Mercury on a Shoreline Trailer
All towed by a 5.7L Hemi Durango.
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