I have a very significant vibration at low to mid rpm on my Yanmar 2GM installed in my Hunter 27. The vibration seems to even out at around 2000 rpm. Not sure where it is comming from but would like some pointers as to where to look. Thanks..
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Check for Growth.
Also, check for growth on the moving parts (shaft, prop, loose zincs). This could significantly cause a vibration problem. Especially if there was no vibration previously.
Also, check for growth on the moving parts (shaft, prop, loose zincs). This could significantly cause a vibration problem. Especially if there was no vibration previously.
I have that problem too
The 2GM in my H31 vibrates as well. Sometimes it seems worse, sometimes it seems better. I usually try to run in an RPM range that minimizes the vibration. Usually faster is better. Try looking an the engine while it is running. It may tell you something. When I first got the boat it was really bad. I eventually found one of the engine mount nuts in the engine sump! It had loosened up and fell off! That in itself was causing serious vibration. I put them both back together with locktite on the bolts. So, check the engine mounts for looseness. I know there is too much play in my cutlass bearing as well. Maybe some of the vibration will subside after replacing the bearing at the next haulout. So, check the cutlass. I also used to have a loud clanging while running. The added sound made it seem like the vibration was much worse. I tracked that down to a loose tray in the galley toaster oven. I stowed it differently and the sound level must have dropped 40dB! So check for things that are vibrating other than the engine. Lastly, I think it seems reasonable to believe that every engine has its good and bad spots on the throttle lever. Mine certainly does, and I try to stick to the good spots while running. Also, I'm not sure we should expect a 2 cylinder diesel to run as smooth as a large gas engine like in a car. This being my first sailboat and diesel engine, I'm not sure half the time what I should expect from it. Please post whatever it is that you ultimately find so I can look for other possibilities on my boat. Paul
The 2GM in my H31 vibrates as well. Sometimes it seems worse, sometimes it seems better. I usually try to run in an RPM range that minimizes the vibration. Usually faster is better. Try looking an the engine while it is running. It may tell you something. When I first got the boat it was really bad. I eventually found one of the engine mount nuts in the engine sump! It had loosened up and fell off! That in itself was causing serious vibration. I put them both back together with locktite on the bolts. So, check the engine mounts for looseness. I know there is too much play in my cutlass bearing as well. Maybe some of the vibration will subside after replacing the bearing at the next haulout. So, check the cutlass. I also used to have a loud clanging while running. The added sound made it seem like the vibration was much worse. I tracked that down to a loose tray in the galley toaster oven. I stowed it differently and the sound level must have dropped 40dB! So check for things that are vibrating other than the engine. Lastly, I think it seems reasonable to believe that every engine has its good and bad spots on the throttle lever. Mine certainly does, and I try to stick to the good spots while running. Also, I'm not sure we should expect a 2 cylinder diesel to run as smooth as a large gas engine like in a car. This being my first sailboat and diesel engine, I'm not sure half the time what I should expect from it. Please post whatever it is that you ultimately find so I can look for other possibilities on my boat. Paul
My Experience
I found that my engine mount bolts had loosened. In the process the engine/tranny to the shaft became mis-aligned. Once I tightened the engine mounts and correctly aligning the shaft with the engine my vibrations went away. The alignment process was really much simpler than I thought it would be.
I found that my engine mount bolts had loosened. In the process the engine/tranny to the shaft became mis-aligned. Once I tightened the engine mounts and correctly aligning the shaft with the engine my vibrations went away. The alignment process was really much simpler than I thought it would be.
my experience
I just purchased a H30 w/2GM. The surveyor noted significant vibration at about 1800 rpms and some wear in the cutlass bearing. I had the mechanic check mounting bolts and shaft alignment, and it was perfect. Mechanic commented that several things could be the cause: 1. It's a 2 cyliner engine; it vibrates. No corrective action available. 2. Prop could be out of balance. Next time the boat is hauled, take it off and take it to the prop shop and have them balance it; don't try to just eye it to tell. 3. The prop shaft could be bent. Check next time the boat is hauled. In the meantime, if it hurts to run at 1800 rpm, don't do it
I just purchased a H30 w/2GM. The surveyor noted significant vibration at about 1800 rpms and some wear in the cutlass bearing. I had the mechanic check mounting bolts and shaft alignment, and it was perfect. Mechanic commented that several things could be the cause: 1. It's a 2 cyliner engine; it vibrates. No corrective action available. 2. Prop could be out of balance. Next time the boat is hauled, take it off and take it to the prop shop and have them balance it; don't try to just eye it to tell. 3. The prop shaft could be bent. Check next time the boat is hauled. In the meantime, if it hurts to run at 1800 rpm, don't do it
Second Andy's solution - realign engine
We had a significant vibration at low RPMs. Our marina checked it and found that one of our engine mount bolts was missing the nut! That was replaced along with all the engine mounts and the engine realigned. Now it runs silky smooth. Our boat is an '87 and the engine mounts were all hard and cracked from age. Be aware! The engine can only be realigned with the boat in the water. The hull changes shape slightly when the boat is out of the water. (According to my marina - they have always done great work) Anyway, we just got back from a two week cruise with not a lot of wind going the right direction. We motored 54 hours and the engine ran like brand new. Last year we were wondering if we would have to replace it.
We had a significant vibration at low RPMs. Our marina checked it and found that one of our engine mount bolts was missing the nut! That was replaced along with all the engine mounts and the engine realigned. Now it runs silky smooth. Our boat is an '87 and the engine mounts were all hard and cracked from age. Be aware! The engine can only be realigned with the boat in the water. The hull changes shape slightly when the boat is out of the water. (According to my marina - they have always done great work) Anyway, we just got back from a two week cruise with not a lot of wind going the right direction. We motored 54 hours and the engine ran like brand new. Last year we were wondering if we would have to replace it.
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