Coupling

Hi new used boat owner and have a quick question. How often should the outdrive be pulled off to grease the coupler? The boat I have is a 2003 bayliner Capri 212. The original owner had it done 3 years ago when he had the boot replaced. I have maybe put a 100 hrs on it since then. It is a 5.0 mercruiser.

dclynch said:

Hi new used boat owner and have a quick question. How often should the outdrive be pulled off to grease the coupler? The boat I have is a 2003 bayliner Capri 212. The original owner had it done 3 years ago when he had the boot replaced. I have maybe put a 100 hrs on it since then. It is a 5.0 mercruiser.

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Ayuh,.... Every year,.... Pull the drive, inspect Everything, check the alignment, 'n Grease everything,...

Alignment tool is $70 to $100 on eBay

Yes, you need to do an engine alignment with it off. For the coupling, you are just greasing the input spline on the driveshaft so that it slides in & out of the coupling freely when needed, like you should also do with the prop. there are more items to lubricate with the drive off, but I won't get into that. It's too much to list. You need a service manual.

Thanks guys that will be the first thing I do when I get it out of storage.

The original owner talking about the coupler has me concerned? Is the coupler bad, does he know and is he trying to cover it up by saying it just needs grease? Grease won't fix a bad coupler! A marine coupler is like a marine clutch, if it goes bad you will get slippage at the prop. Next, a coupler is not too expensive, but more so the outdrive, & engine has to come out of the boat to replace it! This is a lot of labor, and most people don't have the tools, or facilities to do this. Nor the time, or know how.

The first question is
What did the previuos owner have done?
Did he grease the coupler or replace it?

If he replaced it/had it replaced then I would have to assume the motor/coupler was aligned with the gimbal bearing at that time.
If not then that is not good.

One idication would be how difficult it is to remove and re install. If it does not slide easily in 99 % of the way when reinstalling this may idicate a misalignment. Typically the two side by side orings can need a nudge to get into the gimbal bearing.


As far as a single boat owner of one boat goes, it may not be necessary to buy the alignment tool. Not that having it is not a good thing but it may only be needed one time just to confirm the alignment. He could ask a local service place or mobile guy how much to check this. It may be 1/2 the cost, maybe....

Now the coupling,

the grease fitting on the coupler is as said, to grease the male spliines of the drive shaft coming from the outdrive and the female splines in the coupler.

Before this design every mercruiser outdrive had to be removed every year for annual maintenance and the ujoints greased, gimbal bearing greased and the splines greased and the two orings replaced and greased. Now there are three orings and the third is to keep the grease in the coupler.
Also the ujoints "may" be non servicable as all current one are (no greasing needed) and the gimbal bearing may also be nonserviceable as all new and replacements one are (no grease needed) and if this is the case then the outdrive does not typically get removed unless there is a suspected issue. Thus the grease fitting on the coupler to keep the splines lubricated. If they are not then they will oxidize rust together and wear the coupler out prematurely.

So due to nonserviceable components the drives dont get removed very often.

Myself as part of any spring service I pull the drive and grease what needs to be or what I can manually, every drive!! every year!!

Before I bought the boat (it was from a friend that I bought it) What had happened was the boot on the outdrive started leaking so he took it into the marina he bought it from and when they replaced the boot he had them replace the gimbal bearing and anything that could be replaced while the outdrive was off the boat. He had that all done in mid August and I bought the boat the following spring. The main reason the boot leaked was he always parked the boat outside summer and winter. Now that I have it it gets parked in the garage and my truck sits outside, It took me a lot of wax and polishing compound to get the color back from how bad it was faded and I don't want to do that again. So far it has been a great boat we use it mostly for fishing and taking the grand kids for rides.

dclynch said:

Before I bought the boat (it was from a friend that I bought it) What had happened was the boot on the outdrive started leaking so he took it into the marina he bought it from and when they replaced the boot he had them replace the gimbal bearing and anything that could be replaced while the outdrive was off the boat. He had that all done in mid August and I bought the boat the following spring. The main reason the boot leaked was he always parked the boat outside summer and winter. Now that I have it it gets parked in the garage and my truck sits outside, It took me a lot of wax and polishing compound to get the color back from how bad it was faded and I don't want to do that again. So far it has been a great boat we use it mostly for fishing and taking the grand kids for rides.

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You still have not answered the question of wether or not the coupler was replaced. If only the gimbal bearing and ujoint bellows were replaced then I would say the engine was aligned when this was done, so no need for a alignment tool.

If the coupler was also replaced then it would have been aligned for sure as this is standard proceedure for this type of repair.

So if you simply grease every fitting and if you can find and reach the coupler grease fitting then grease away......

If you can not get to the coupler grease fitting as many are not easily accessable then the outdrive has to come off in order to grease the splined drive shaft.

So a manual would be a great asset to do this so you get a understanding on what is what and how to.........

Here is the only pic I could come up with showing a coupler grease fitting. This is behind the engine block in the center. you should see the drive shaft entering the coupler....may be able to and may not be able to, all depends on the boat design..........