I have a loud, regular and rhythmic knocking that seems to be coming from the prop-shaft area on my Hunter 31, when the boat is in gear. It is a new shaft, a newly-trued prop, but the problem predates these replacements. Noticed it after hanging up on a buoy cable, which bent the prop a little and the shaft a little less (shaft has since been replaced). The engine's (Yanmar 2GM) been checked out as fine, but the motor mounts, I have noticed, are shaking themselves loose. Before I throw more money at the boatyard, does anybody have any theories? Might this be an allignment issue? That's the mechanic's theory. Never checked or fixed that myself. Doable for a near-novice? Thanks for any suggestions.
knocking in the drive train
- Thread starter roger5044
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Alignment and/or the strut.
Roger: It seems to me that you could have a bent strut (and that is not good). The motor mounts may be worn and you may need an alignment too. The motor mounts are about $400 for all four plus installation. Be sure you need them before you purchase them. There have been posts about using brand X mounts, but I believe that folks who have been to the Yanmar classes indicate that these unit are NOT recommended.
Roger: It seems to me that you could have a bent strut (and that is not good). The motor mounts may be worn and you may need an alignment too. The motor mounts are about $400 for all four plus installation. Be sure you need them before you purchase them. There have been posts about using brand X mounts, but I believe that folks who have been to the Yanmar classes indicate that these unit are NOT recommended.
Check the shaft log
After wrapping a line around the prop and shaft which bent a few things, the rhythmic knock was coming from the shaft hitting the side of the shaft log. It wasn't touching by much. Jim S/V Java
After wrapping a line around the prop and shaft which bent a few things, the rhythmic knock was coming from the shaft hitting the side of the shaft log. It wasn't touching by much. Jim S/V Java
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