During our third season (summer 99') on our Hunter 280, we developed a loud vibration when running our Yanmar 2gm at two different rpm's, low (I forget where),& high (maybe around 2100). It smooths itself out anywhere else. Does this sound normal, or does this sound like a problem with a bearing (ouch!). While still in the yard, I have looked at the shaft, and it feels stiff (can't wiggle it), but where it exits the hull, it doesn't appear to be centered in the fitting, even when I rotate the shaft, it stays in the same low position. I peeked at another 280 in the yard, and theirs was centered. Any suggestions?
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Check your engine mounts...
One problem that could explain most of the symptoms that you describe is that the rubber shocks in the original engine mounts might have become compressed far enough to produce metal-to-metal contact, particularly when the engine vibrates a little more at certain rpm ranges. We are just getting ready to fix a similar problem on our Legend 43 "Rivendel II". At any rate, you seem to have an alignment problem that is worth having a professional look into. Flying Dutchman
One problem that could explain most of the symptoms that you describe is that the rubber shocks in the original engine mounts might have become compressed far enough to produce metal-to-metal contact, particularly when the engine vibrates a little more at certain rpm ranges. We are just getting ready to fix a similar problem on our Legend 43 "Rivendel II". At any rate, you seem to have an alignment problem that is worth having a professional look into. Flying Dutchman
check this
The lag bolts that bolt the mounts to the hull loosened up on my boat. Check them at least once per season.
The lag bolts that bolt the mounts to the hull loosened up on my boat. Check them at least once per season.
Alignment
I have a 1989 H30 and have had a knocking at most rpms under power. when I checked the shaft alignment, I found it was not centered in the shaft log. When I first checked, I didn't find the center position and just checked flange to flange. The procedure is to uncouple the shaft - pust down till it touches the shaft log and note the position. Pull up till it touches the top - same left and right and block to that position - THEN check the flanges and position the engine accordingly. Mine was 3/16" too low. I am sure my mounts have sagged - but it doesn't knock anymore. Making a wedge with two pieces of wood cut at a 30 deg or so angle works to prop the shaft in position.
I have a 1989 H30 and have had a knocking at most rpms under power. when I checked the shaft alignment, I found it was not centered in the shaft log. When I first checked, I didn't find the center position and just checked flange to flange. The procedure is to uncouple the shaft - pust down till it touches the shaft log and note the position. Pull up till it touches the top - same left and right and block to that position - THEN check the flanges and position the engine accordingly. Mine was 3/16" too low. I am sure my mounts have sagged - but it doesn't knock anymore. Making a wedge with two pieces of wood cut at a 30 deg or so angle works to prop the shaft in position.
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