Best Replacement Engine Coupler for Mercruiser

[max4owner]

Hi guys,What is the best manufacturer of a replacement hub? I really don't want a Mercruiser again if it just last 6 years or so. I have a 1990 4.3L Alpha 1 with 560 hours.While I haven't actually pulled the covers off yet, I'm pretty sure I spun an engine coupler this weekend. It has occured before and I have a solid prop (Land-n-Sea Torque Shifter), so I know it is not a spun prop hub. And - no - I did not align my engine every year. I believe I most likely will have to now. It could be a weak floor or transom as a source, I just don't know. Finally, I've had a "roar" that is engine speed related that started last year. It's actually quite loud. I pulled the top gear cover and those seem fine. The dealer though it was a water pump, but he checked that out and it was OK. What is your guess - drive shaft U-Joints, Coupler, Input shaft bearings?

[Bond-o]

Sounds like your Maintenance Schedule has been Lax.......I'm Guessing your Roar is the Gimbel Bearing........That's the Other Half of the Alignment Thing................Mercruiser Probably makes the Best Coupler,But, NAPA sells Aftermarket Couplers.....

[achris]

I had a 165 (inline 6) for 8 years (was 14 years old when I bought it) and never had a coupler problem. I have had the current engine (4.3LX) for 10 years with out a sound from it. Like Bondo says, you have an issue with correct alignment.Chris............

[max4owner]

I just pulled the outdrive. The gimble bearing is gone (it is the source of the grrrrrrrrr) and so is the bellows. You guys were right on that one. But the alignment was OK (I have the alignment tool, so there really wasn't an excuse for not checking), if the coupler can still be tested in this manner. It did, after all, keep the boat moving with the engine running at around 2000 RPM. Maybe there is a bit of play in the gimble bearing now and that plus some coupler play may be providing the slack.Is there possibly anything else I'm missing?Sure would like to know who else make couplers . . . Would someone have the NAPA part number?

[achris]

Why are you looking for a second source? The Merc unit is very good. You've found the cause of the failure and it's not the coupler. If the coupler has been chewed up it was the dead gimbal bearing that caused it.Stick with OEM. They're made by Mercury for Mercury.Chris...........

[Trent]

Aftermarket Coupler

[max4owner]

Thanks everyone for your advice. The most logical cause of this chain failure is torn bellows deterioriates gimble bearing (rust and play in the housing) and quickly that takes out the engine coupler. Alignment was fine. Which is good because some concern about floor and transom rigidity. I sure hate wood!The unfortunate chain failure is the result of not being used much. Last year, the boat received a new floor and was used twice. That is when the roaring started. This year, the boat received a new interior and this was the first time out. So I didn't do a lot of normal checking. Bad mistake. I would still be faced with the gimble bearing bellows, but perhaps not the gimble bearing and engine coupler. On top of the above, the new floor is delaminating around the ski locker. So it will have to go back to the fiberglass guy this fall.So, it's time to go to work! Again - thanks to the responders.