Cutlass bearing worn?

[Scott T-Bird]

I had my new Yanmar 2YM15 installed this spring and finally had her in the water by the middle of June so the engine is still just breaking in (and probably will be for a long time). With just 10 hours so far, the engine usage is light!

At about 3000 rpm and above, I've noticed a rattle that sounds like it is coming from the area where the cutlass bearing is. The mechanic claims that he was very sure about alignment, but he thought the bearing was a little sloppy. He said not enough to make an issue since he didn't want to delay the splash date by that time. But he says he is surprised that I noticed the noise because he thinks alignment is very good and the bearing not too bad.

I never noticed any looseness in the past, but my top rpm with the old 1GM was just 2400 rpm, to some extent because of being over-prop'ed. Now, the same prop seems perfectly matched.

The engine also idles very smoothly in gear when at idle throttle, but as I ease it up to leave the slip, I often notice a brief shudder when just nudging the throttle slightly. I observed the engine when this happens (with Sue at the helm) and noticed a very brief vibration at the back end of the transmission ... enough that the PSS spits a little water at a certain rpm just above idle. That has puzzled me as well.

I know that they didn't use new set screws and they must have loosened them when dis-coupling the shaft, so ordering new screws and replacing them with a new PSS setting is on my to do list. I get a minor amount of water leakage from the shaft when running for a period of 15 minutes or more.

Any thoughts would be appreciated!

 

[Tim R.]

Scott, make sure none of the engine mount adjusting nuts have worked loose. Could also be related to the damper plate although that should not affect vibration at the shaft.

Was the alignment done in the water? Was it done after the boat had been in the water for a couple of weeks to let it settle and take proper shape in the water?

 

[Milton Critz]

Tim is correct, the boat should be in the water for a couple of weeks before the final alignment of shaft coupling. Another thing that can cause the cutlass bearing to rattle is the balance of the prop. It may have vibration points much like tires on a car. They are fine at 50 mph but shake like crazy at 70 mph and smooth out again at 75. The alignment should the first thing to check as it is the easiest. Prop balancing requires hauling the boat and a good prop shop.

 

[Scott T-Bird]

Hauling the boat is going to be early this year, as the drawdown is going to start in September ... this is the 5-year drawdown where they take the lake down about 6'.

No, the alignment has not been looked at since the boat has been in the water. I'll check it out now that it has been in at least a month. I'll have plenty of time this fall to sort it out, unfortunately.

 

[Chris Patterson]

All true Scott. I'm continually amazed at just HOW close these things need to be. I will not splash a boat any more without changing the cutlass. It's under the water, only costs 40 bucks, and even on the hill it's a super pain changing one with the shaft in it. Underwater? Fuggetaboutit..

And as said. If it's fresh, go ahead and loosen the four bolts holding the coupling together. Three thousandths or less is my benchmark.

(i launched one one time with the old bearing. Felt good, very little play. So in ya go. The damn thing shook so hard it was rattling stuff up the mast, I genuinely thought the motor was missing a cylinder. New bearing, end of problem. And I hope that's not it for you, it's way much easier to realign the coupler)..

 

[Charlie Jones s/v Tehani]

Just to be a curmudgeon- it's a CUTLESS bearing.

I know now a days the two are used interchangeably, but it was patented as "cutless".

Doesn't really matter of course, just as I said, being a curmudgeon.

Big Grin

 

[Maine Sail]

Just to be a curmudgeon- it's a CUTLESS bearing.

I know now a days the two are used interchangeably, but it was patented as "cutless".

Doesn't really matter of course, just as I said, being a curmudgeon.

Big Grin

"Cutless® is a registered trademark of Duramax Marine® LLC."


Cutless is a registered trade name owned by Duramax. Cutless is a brand not a necessarily a generic term for the bearing.. The accepted generic terms are cutlass bearing, stave bearing or sleeve bearing. Cutlass is regularly used & accepted industry wide because using the word Cutless is a trademark infringement on Durmax Marine..

Even massive world wide marine manufacturers such as Vetus (Vetus Cutlass Bearings) use the term Cutlass because they can't use the word Cutless®

 

[Chris Patterson]

oh god....i shoulda known better than to say anything here again...................................................................................................................................................................................................................................................................................................................................................................................................................................................................

 

[Scott T-Bird]

Thanks for the input on the "sleeve bearing". It shouldn't have been any big deal to replace it when they could, so I'm a little miffed ... but the opportunity will come soon enough. Thunderbird was constructed with an offset shaft to the port side, so the shaft can be removed without dropping the rudder, which seems like it would be the bigger problem.

As an aside, I've never dropped the rudder out in the 9 years of owning the boat ... should I inspect it? I've never had reason to suspect any problems. I assume that the rudder would have to be dropped while the boat is in the slings in the fall, and then replaced when in the slings again in the spring.

Back to the engine ... I have a little concern about the slight shudder I feel when nudging the throttle ever so slightly to exit the slip (in forward gear). I seem to notice it more going forward (I back into my slip) but it does seem to persist with rpm around 1000 to 1200. Idle rpm (in forward gear) is about 800 and there is no vibration, and over 1200 all is smooth. I don't think it is related to the sleeve bearing (or would it?).

Any thoughts? I'd like to demonstrate directly to the Yanmar dealer, but without a dealer anywhere on the lake or nearby, that is a logistical problem. I will be demonstrating on the water with the marine mechanics who did the install, but at their prices, I like to be more certain with my understanding before enlisting their services.

I have a pretty good relationship with these guys over the last 9 years ... I have to because they are my only option on this lake (basically, I pay them well and they treat me with respect and solid service). After I took the boat to my slip (another location) Barry told me later he wasn't quite ready for me when I took it - even though the manager said go ahead. He had some odds and ends to clean-up, which I noticed and did on my own. When I'm ready to take the boat back to them, I believe they will resolve any issues I have but I want get an idea, first.

 

[NYSail]

Take your camera phone down there and record a video of it for them. Then you can email it anywhere to anybody.

Also you can jump in the water and inspect the sleeve bearing. If its bad you will feel play when you shake the shaft. Should be relatively snug. With a mask you will be able to see wear if you have good access.

Good luck

 

[Charlie Jones s/v Tehani]

Maine Sail- Hence the use of "Curmudgeon" and "Big Grin"

 

[Maine Sail]

Maine Sail- Hence the use of "Curmudgeon" and "Big Grin"

Hence the winkie at the end of mine.....