I have a Yanmar 2GM. It starts easily and runs well, however, it does vibrate and the prop shaft has vibration. A friend thinks it vibrates excessively but I am not sure. I just started it this season (no problem) and ran the engine about 20 minutes. He noticed the vibration then. Is this something that will improve as I use it more this season?
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When does the vibration occur?
I have a 2GM20F in my 29.5 that vibrated a lot at low rpm's when idling at startup. My solution was to adjust the idle about 100 rpm higher, There's much less vibration now. If the vibration occurs when motoring in gear, does it happen at certain rpm's or at all rpm's? An engine mount could be bad or the alignment could be off.
I have a 2GM20F in my 29.5 that vibrated a lot at low rpm's when idling at startup. My solution was to adjust the idle about 100 rpm higher, There's much less vibration now. If the vibration occurs when motoring in gear, does it happen at certain rpm's or at all rpm's? An engine mount could be bad or the alignment could be off.
Aligning a shaft is not easy
nothing says you can't do it, but..... I have a 2 cylinder that had a lot of vibration. New engine mounts were required, but it made a world of difference.
nothing says you can't do it, but..... I have a 2 cylinder that had a lot of vibration. New engine mounts were required, but it made a world of difference.
Could Be One or Two of Many Things
Endless Summer (h31) has a 2GMF. We have vibrations at certain RPM's so we don't run at those RPM's. I pulled the injectors and had them serviced (first time since 1983) and it made the engine run more smoothly. Does your engine vibrate in forward gear only? or in neutral only? or what? We had a vibration problem a long time ago and it turned out to be sticky injectors probably due to low sulfur diesel fuel. We use an additive called Biobor and we no longer have that vibration problem. If the vibration is only in gear, it could be engine alignment, shaft needs truing and/or prop need truing. The engine alignment procedure is described in lots of manuals and it is not hard to do. Just time consuming, frustrating and uncomfortable. So, diesel vibrations can be caused by lots of things. Good luck. Roger Mummah remummah@worldnet.att.net
Endless Summer (h31) has a 2GMF. We have vibrations at certain RPM's so we don't run at those RPM's. I pulled the injectors and had them serviced (first time since 1983) and it made the engine run more smoothly. Does your engine vibrate in forward gear only? or in neutral only? or what? We had a vibration problem a long time ago and it turned out to be sticky injectors probably due to low sulfur diesel fuel. We use an additive called Biobor and we no longer have that vibration problem. If the vibration is only in gear, it could be engine alignment, shaft needs truing and/or prop need truing. The engine alignment procedure is described in lots of manuals and it is not hard to do. Just time consuming, frustrating and uncomfortable. So, diesel vibrations can be caused by lots of things. Good luck. Roger Mummah remummah@worldnet.att.net
Vibration In-Gear?
If the vibration is new this season and does it when it's in gear, possibly it could be the result of zincs which have lost material more on one side than the other. Another sign of something that is related to the drive train is if the vibration occurs more at intervals of certain rpms, say, 800, 1600, 2400, for example. A rough running engine could be the result of uneven fuel feed: dirty filters maybe due to microorganisms (change filters), air in the line (bleed to get air out), air leak somewhere in the fuel suction line. The above are the cheap and easy to fix items.
If the vibration is new this season and does it when it's in gear, possibly it could be the result of zincs which have lost material more on one side than the other. Another sign of something that is related to the drive train is if the vibration occurs more at intervals of certain rpms, say, 800, 1600, 2400, for example. A rough running engine could be the result of uneven fuel feed: dirty filters maybe due to microorganisms (change filters), air in the line (bleed to get air out), air leak somewhere in the fuel suction line. The above are the cheap and easy to fix items.
...Alignment
I had the same problem. I would get a vibration at both a low and a high rpm. At first I would adjust my rpm's and it quieted down. Then my mechanic pointed out my alignment problem. I left him to it, and he corrected it in about twenty minutes (or at least thats what he charged me for). She now runs smooth as silk... My mechanic also explained to me that if I let it go any longer, my 2GM would have jumped right off its mounts!
I had the same problem. I would get a vibration at both a low and a high rpm. At first I would adjust my rpm's and it quieted down. Then my mechanic pointed out my alignment problem. I left him to it, and he corrected it in about twenty minutes (or at least thats what he charged me for). She now runs smooth as silk... My mechanic also explained to me that if I let it go any longer, my 2GM would have jumped right off its mounts!
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