My question is, what is the effect of overfilling the lube oil in the transmission of a Yanmar 1GM10 engine? It looks like a previous owner has filled the oil to the dipstick mark without screwing in the dipstick. The Yanmar manual specifies that the fill level be checked with the dipstick screwed in. The result is more than twice as much oil in the tranny as specified. The reason I am asking this is, I am having a problem with major vibration/shuddering under power on my boat. The boat is a C&C 27 Mk 5 with the Yanmar 1GM10 engine. Power is smooth in gear up to about 1800 RPMs, then begins to shake, more and more violently as RPMs increase. The engine runs very smoothly in neutral at any RPM from 800 to 3600 - the problem is only in forward gear. The engine does not smoke excessively. The motor mounts are good. I have had the prop shaft replaced with a new stiff high grade SS shaft, the tranmission coupler replace with a new "split" style, had the coupler/shaft professionally machined and aligned, and replace the cutlass bearing. The prop is a Gori "geared" style 2 blade folding prop in like new condition, and the diameter and pitch are correct for the boat. (Sometimes, when the shaking is not too bad, I can get up to 3400 RPM in gear, and the boat will exceed hull speed under power.) But none of this has had any effect. Most days I cannot power over 3.5 knots. So I am wondering if the problem is the cone clutch in the transmission, and if the oil level could be the cause. Any ideas?
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chris
similar problem
I have a similar problem. I wonder if it's the same. The engine is fine in N no adverse noise or vibration. In gear there is a vibration.. ( maybe grinding noise ) which gets worse as the rpm's increase. Reverse is fine. I have had everything looked at and can't find the problem. Please let me know if you find any answers. Yanmar 40 on a sabre 38. chris chris@tidesedge.com
I have a similar problem. I wonder if it's the same. The engine is fine in N no adverse noise or vibration. In gear there is a vibration.. ( maybe grinding noise ) which gets worse as the rpm's increase. Reverse is fine. I have had everything looked at and can't find the problem. Please let me know if you find any answers. Yanmar 40 on a sabre 38. chris chris@tidesedge.com
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Vic
I would open what panels I can to see ...
the shaft, trans and engine and then have someone run it while you are right near the engine, shaft, trans. I had a folding prop a while ago that made a hell of a racket above 2500 ... like an unbalanced tire. If you can feel the area about the cutlass bearing and feel more vibration there than near the transmission you probably have an out of balance condition somewhere after the trans. the 1G has the most vibration of any of the yanmars anyway and it could also be something at the motor itself. Last I remember overfilling oil wouldn't cause this kind of vibration ... as long as it doesn't look frothy and is breaking down. Vic "Seven"
the shaft, trans and engine and then have someone run it while you are right near the engine, shaft, trans. I had a folding prop a while ago that made a hell of a racket above 2500 ... like an unbalanced tire. If you can feel the area about the cutlass bearing and feel more vibration there than near the transmission you probably have an out of balance condition somewhere after the trans. the 1G has the most vibration of any of the yanmars anyway and it could also be something at the motor itself. Last I remember overfilling oil wouldn't cause this kind of vibration ... as long as it doesn't look frothy and is breaking down. Vic "Seven"
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Jimmy Harrell, Hunter 37 C
Transmission to Prop Shaft Coupler
On the next cruise after having the transmission/prop shaft repaired we had a slight vibration which suddenly go so bad that we thought we were going to have to be towed from a fairly remote area of the Everglades (Little Shark River). Turns out that three of the four bolts holding the transmission to prop shaft coupler were out and the fourth was holding on by only a few threads. We found the missing bolts and were able to make the repair. Vibration was essentially eliminated. We were lucky.
On the next cruise after having the transmission/prop shaft repaired we had a slight vibration which suddenly go so bad that we thought we were going to have to be towed from a fairly remote area of the Everglades (Little Shark River). Turns out that three of the four bolts holding the transmission to prop shaft coupler were out and the fourth was holding on by only a few threads. We found the missing bolts and were able to make the repair. Vibration was essentially eliminated. We were lucky.
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james rohr
safety wire the bolts
A few years ago mine developed vibration also. found that bols on the shaft coupler had loosened. (I did'nt have the bolts properly safety wired.) tighened bolts and re safety wired, vibration then went away. If the heads of the bolts don't have hole in them you may have to buy new one or drill holes for wire. stainless wire can be purchased from most plumbing supply houses or industrial supply houses.(ww granger)
A few years ago mine developed vibration also. found that bols on the shaft coupler had loosened. (I did'nt have the bolts properly safety wired.) tighened bolts and re safety wired, vibration then went away. If the heads of the bolts don't have hole in them you may have to buy new one or drill holes for wire. stainless wire can be purchased from most plumbing supply houses or industrial supply houses.(ww granger)
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Marcus Reichert
Transmission vibration
YOu probably have checked this but my dad has a folding prop on his ERcison 32 and at times the blades will not fully flip open causing so much vibration that it feels like the boat is going to come apart. Good luck!
YOu probably have checked this but my dad has a folding prop on his ERcison 32 and at times the blades will not fully flip open causing so much vibration that it feels like the boat is going to come apart. Good luck!
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Tom
Are your Shaft Zincs loose?
While they "might" be on ok, if they are not really tight they might slip on the shaft under power or higher shaft speed. Might be the reason why the "vibration" comes and goes also. Sometimes the zinc is "slipping" and sometimes its not. I know this because I've had this happen to me in the past. Did you tap them with a hammer and then tighten the screws and then tap them some more and re-tighten until they were on so tight you couldn't screw down the screws anymore? That is the only way to ensure that the zinc is on tight . I would dive on the shaft with a screwdriver and see if I could tighten the zinc screws at all. If you can tighten the screws more than one revolution, then you might have found your problem.
While they "might" be on ok, if they are not really tight they might slip on the shaft under power or higher shaft speed. Might be the reason why the "vibration" comes and goes also. Sometimes the zinc is "slipping" and sometimes its not. I know this because I've had this happen to me in the past. Did you tap them with a hammer and then tighten the screws and then tap them some more and re-tighten until they were on so tight you couldn't screw down the screws anymore? That is the only way to ensure that the zinc is on tight . I would dive on the shaft with a screwdriver and see if I could tighten the zinc screws at all. If you can tighten the screws more than one revolution, then you might have found your problem.
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Bob England
Transmission vibration - thanks
Thanks to everyone for the excellent suggestions. I have checked most of them out, the ones that I can do with the boat in the water. My best theory is that the cone clutch is chattering if it doesn't seat correctly when shifted into forward. One tip I got from the Torresen Marine Web site that seems very helpful is that the Yanmar transmissions need to be shifted quickly -- snap the shift lever -- to make a clean shift. When I do that the clutch is more likely to transmit the engine power smoothly. Another tip is to change the tranny oil when experiencing a slipping clutch. Mine isn't slipping, it's banging! But I've also done that and I'll see what effect it has the next time I'm out on the water. Thanks again.
Thanks to everyone for the excellent suggestions. I have checked most of them out, the ones that I can do with the boat in the water. My best theory is that the cone clutch is chattering if it doesn't seat correctly when shifted into forward. One tip I got from the Torresen Marine Web site that seems very helpful is that the Yanmar transmissions need to be shifted quickly -- snap the shift lever -- to make a clean shift. When I do that the clutch is more likely to transmit the engine power smoothly. Another tip is to change the tranny oil when experiencing a slipping clutch. Mine isn't slipping, it's banging! But I've also done that and I'll see what effect it has the next time I'm out on the water. Thanks again.
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