I have a 1983 Hunter 34 with a 21HP yanmar. I get a serious vibration between 1700-2300 RPMs. Otherwise it is smooth. The service dept. in my marina first aligned the engine and shaft, then replaced the motor-mounts, and finally (when the first two failed to cure the problem) remounted the strut (they told me it was loose)and replaced the cutless brg. Now they tell me the wood in the stringers has rotted, which is why the bolts holding the steel channel to the stringers are loose. I had a surveyer check the stringers and there is not problem with the wood. I was able to tighten most, and the one that is stipped I can through bolt. The "new" cutless brg. has a lot of play, and the prop appears to be somewhat off. I believe the problem begins at the prop, and may be a combination of a shaft that is not true, the loose bolts at the stringers, and the prop. Any suggestions? I'm a new owner who is learning fast $$!
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Mitchel Stroh
New prop
I had a similar problem, above 2200 RPM lots of vibration. Ordered new 3 blade prop from West by North (www.westbynorth.com) no more vibration.
I had a similar problem, above 2200 RPM lots of vibration. Ordered new 3 blade prop from West by North (www.westbynorth.com) no more vibration.
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TOMMY MCNAMARA
Vibration
Ask an old timer and then see a macanic not a parts man or buy a new boat, seems like your headed that way
Ask an old timer and then see a macanic not a parts man or buy a new boat, seems like your headed that way
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R.W.Landau
shaft
My thought on this is that the bolts,strut,etc are loose due to the vibration. Have they checked the shaft? Is it true? The cutless sounds like the wrong one for the shaft. This would allow the shaft to create a vibration. Has the prop been pulled and checked to make sure it has not been bent? Sounds like a limited problem that can be traced. You may have to forgo other advice and figure it out yourself, then get someone to repair it if you can not. I would start by looking at the shaft while doing between 1700 and 2300 rpm. If you see the vibration, it is most likely from the motor back. This leaves three parts. 1. The shaft. You may even be able to see the distortion while running if you can see enough shaft. 2. The propeller. Have it pulled and take it to a good prop shop. They can check it. 3. The strut/ Cutless. If there is play in the cutless, it is the wrong size! Let us know how it's going. Good luck, r.w.landau
My thought on this is that the bolts,strut,etc are loose due to the vibration. Have they checked the shaft? Is it true? The cutless sounds like the wrong one for the shaft. This would allow the shaft to create a vibration. Has the prop been pulled and checked to make sure it has not been bent? Sounds like a limited problem that can be traced. You may have to forgo other advice and figure it out yourself, then get someone to repair it if you can not. I would start by looking at the shaft while doing between 1700 and 2300 rpm. If you see the vibration, it is most likely from the motor back. This leaves three parts. 1. The shaft. You may even be able to see the distortion while running if you can see enough shaft. 2. The propeller. Have it pulled and take it to a good prop shop. They can check it. 3. The strut/ Cutless. If there is play in the cutless, it is the wrong size! Let us know how it's going. Good luck, r.w.landau
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R.W.Landau
another thought
If the engine was aligned with loose bolts you may have to go back to aligning also. If you look at the shaft while running, look at the engine/shaft face plates. You should be able to see a slight distortion or strobe type of movement. I would still concentrate on the alignment to the prop. If you have used ether to start your engine, you may have bent the crank but I think you would hear and see more evidence of a bent crank.(the vibration would not stop) again, good luck r.w.landau
If the engine was aligned with loose bolts you may have to go back to aligning also. If you look at the shaft while running, look at the engine/shaft face plates. You should be able to see a slight distortion or strobe type of movement. I would still concentrate on the alignment to the prop. If you have used ether to start your engine, you may have bent the crank but I think you would hear and see more evidence of a bent crank.(the vibration would not stop) again, good luck r.w.landau
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Duane Cady
Same Problem -- How serious ?
I have a'84 H31 that exhibits the same problem. I went most of the season last year with a vibration in the RPM ranges described. It smooths out nicely at 2500, and sometimes shows no vibration at all. Im just wondering in light of this discussion if I should put alot of time and $$$ into fixing it before next year (when I haul the boat). Aside from the annoying vibes while going through that rpm range, what kind of long-term (read expensive) damage can this do to the boat ? Any experiences here ? Duane
I have a'84 H31 that exhibits the same problem. I went most of the season last year with a vibration in the RPM ranges described. It smooths out nicely at 2500, and sometimes shows no vibration at all. Im just wondering in light of this discussion if I should put alot of time and $$$ into fixing it before next year (when I haul the boat). Aside from the annoying vibes while going through that rpm range, what kind of long-term (read expensive) damage can this do to the boat ? Any experiences here ? Duane
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Kevin l. Woody
Vibration problems.
Hello Tom, Sorry hear about the $$ education. I think that repair persons often focus with “above the water line” items first and not with the real culprits the “below the water line” items. We, here at PYI, choose to always look at the propeller first and work our way back up the shaft. We believe that it is more common for a propeller to experience problems, over the rest of the running gear, because of its exposure to the elements. If the propeller is found to be ok, we then start to work our way up the line to the engine. Intermittent vibrations are almost always the worst kind to figure out. Harmonics are very difficult to isolate because so many things can cause them. A few items come to mind. Excessive load being created by the propellers diameter or pitch. Bent or damaged propellers, shafts and struts. Overly loose cutlass bearings. Damaged couplings or excessive shaft movement in the coupling. Damaged motor mounts. Damaged or worn out damper plates. Engine out of balance, (injector clogged or partial blockage?) We would suggest that you start this season by removing the propeller, shaft and coupling and have a prop shop confirm the “fit and face” and balance/track the propeller. Remove the loose cutlass bearing and replace it with a proper fitting one. Once the vessel is back in the water align the coupling and shaft back to the engine. This way you can be assured that the drive gear “under the water line” is ok. If your problem still persists you can focus with the items above the water line. Hope this helps. Sincerely, Kevin L. Woody
Hello Tom, Sorry hear about the $$ education. I think that repair persons often focus with “above the water line” items first and not with the real culprits the “below the water line” items. We, here at PYI, choose to always look at the propeller first and work our way back up the shaft. We believe that it is more common for a propeller to experience problems, over the rest of the running gear, because of its exposure to the elements. If the propeller is found to be ok, we then start to work our way up the line to the engine. Intermittent vibrations are almost always the worst kind to figure out. Harmonics are very difficult to isolate because so many things can cause them. A few items come to mind. Excessive load being created by the propellers diameter or pitch. Bent or damaged propellers, shafts and struts. Overly loose cutlass bearings. Damaged couplings or excessive shaft movement in the coupling. Damaged motor mounts. Damaged or worn out damper plates. Engine out of balance, (injector clogged or partial blockage?) We would suggest that you start this season by removing the propeller, shaft and coupling and have a prop shop confirm the “fit and face” and balance/track the propeller. Remove the loose cutlass bearing and replace it with a proper fitting one. Once the vessel is back in the water align the coupling and shaft back to the engine. This way you can be assured that the drive gear “under the water line” is ok. If your problem still persists you can focus with the items above the water line. Hope this helps. Sincerely, Kevin L. Woody
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Gary A
Three Blade Prop
Hey Mitchell, What were the specs for the 3-blade prop for a Hunter 34? I've been thinking about changing to a 3-blade prop myself. Are you pleased with it? Did it make a noticable difference in your sailing speed (decrease) or motoring speed (increase)? Thanks, Gary
Hey Mitchell, What were the specs for the 3-blade prop for a Hunter 34? I've been thinking about changing to a 3-blade prop myself. Are you pleased with it? Did it make a noticable difference in your sailing speed (decrease) or motoring speed (increase)? Thanks, Gary
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Mitchel Stroh
Gary - Three Blade
I installed the prop in late November just before winterizing. So I have not sailed the boat with the new prop and have only motored once but that once was surprisingly smooth. Even if I lost some sailing speed the absence of vibration and increased motoring speed will be worth it. I don’t remember the prop size, I can look it up if you need me to. All I did was call West by North and give them Boat information and they sized the prop.
I installed the prop in late November just before winterizing. So I have not sailed the boat with the new prop and have only motored once but that once was surprisingly smooth. Even if I lost some sailing speed the absence of vibration and increased motoring speed will be worth it. I don’t remember the prop size, I can look it up if you need me to. All I did was call West by North and give them Boat information and they sized the prop.
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