Coupler

[DonziJon]

I've seen threads over the years talking about the engine "Coupler'. In this case I'm curious about the 350...Alpha 1, mid 80s. Most seem to suggest there is a RUBBER mounted female spline in the coupler....and when they go you smell rubber burning. Was there also a Solid Coupler..No Rubber..? Just wondering. DJ

[gcarter]

The Alpha coupler is pretty small, only about 3"-4" in diameter, so not alot of bonded area, or cushion.
When the coupler died on the Minx, I installed a Bravo coupler, which necessitated a Bravo flywheel cover (larger diameter rear oopening to accomodate the larger diameter Bravo coupling.
All the newer engines come w/the larger opening flywheel cover, even the 3.0 so it's easier to change to the Bravo coupler.
No coupler isn't a good idea since there's no shock absorbing hydraulic transmission like a Velvetdrive. Even the Velvetdrive has a two part flex plate with radially mounted compression springs to take the shock.

[DonziJon]

George: Did some of the boats come with a solid coupler..NO rubber..?? Is there such a thing as a SOLID ..NO rubber coupler..??

[gcarter]

George: Did some of the boats come with a solid coupler..NO rubber..?? Is there such a thing as a SOLID ..NO rubber coupler..??

I'm not aware of any, there's even a heavy duty rubber coupler w/a longer spline.

[mrfixxall]

you wont find a solid coupler in any bravo or alpha mr, r , alpha 1 gen 1 or 2..then only thing close to solid mounting would be one with a transmission and ever they have a flex plate with springs to cushion it,,kinda looks like a clutch plate..

[LKSD]

The HD bravo coupler is the strongest coupler you would want for a merc alpha or bravo set up.

[Pismo]

when you switch to a bravo coupler, does the alpha drive spline still fit?

[LKSD]

Yes, Same spline configuration..

[DonziJon]

Here's why I asked. When I pulled my Alpha I (NEW Gen I.. ~25 hours old.), the square section gasket that seals the drive to the bell housing was chewed up in the 5 O'Clock position. Also: one of the Tabs/Lugs that is part of the retainer ring for the bearing assembly was knocked off...at the same position.. Apparently the U-Joint struck the retainer ring tab and broke it off...and chewed the gasket...if for only an instant.

When I first put the boat in the water this season..I REMEMBER..the engine didn't fire up right away so I added some throttle. The engine fired up (Elevated Revs) and I IMMEDIATELY noticed the drive was full up.....I lowered it immediately. Never thought any more about it until I pulled the drive yesterday after 10 hours use....and noticed this anomaly.

I also noticed the U joint spline was actually TWISTED. WTF: How could that happen? Apparently the coupler is the stronger component...Vs the yoke spline.

So I think I'm going to replace the tabbed retainer ring...if only to support the square section gasket next time. I am really surprised that the U joint spline shaft was so SOFT as to twist. I may replace the twisted spline shaft as well...but I'm not convinced that it would be a problem if I didn't. DJ

[gcarter]

It wouldn't hurt to replace the shaft if you're replacing the joints. There's usually a bunch for sale on eBay.

[MOP]

Couplers will take a lot of shock it is not so much the power "within reason" put to it as it is alignment. Spot on alignment will keep it in good condition longer then some engines. Early on 454's were mated to Alphas in all size applications including a lot of our smaller 22 classics. Another thing that is overlooked by many is re-lubing the splines, left to dry out if water gets splashed up many times they will freeze. When they freeze in the coupler the only way out is a cutting torch to sever the shaft. Kenny's 22spun the splines out of the couple a couple of years back, I am sure if properly lubed it would no have happened. Make it a point to pull your drive at the very least every other season up north and annually down in the warmer climes, and yes recheck the alignment. Phil

[DonziJon]

Thanks guys for the input: Can that bearing assembly Retainer Ring with the lugs/tabs, be removed OVER the U-joint..without removing the U-Joint or bearing assembly from the drive..?

It looks like it will clear. Just wondering. I'm not going to do it myself because I need a special retainer ring wrench. I just want to be informed when I go to the tech. DJ

[mrfixxall]

Thanks guys for the input: Can that bearing assembly Retainer Ring with the lugs/tabs, be removed OVER the U-joint..without removing the U-Joint or bearing assembly from the drive..?

It looks like it will clear. Just wondering. I'm not going to do it myself because I need a special retainer ring wrench. I just want to be informed when I go to the tech. DJ

you have to remove the whole assembly to change it..once removed from the drive their is a nut on the back side of the gear then the yoke and u joint assembly Will slide out..their is a preload torque on the carrier bearing assembly..
also merc has its own spline greece that like peanut butter..

[Donziweasel]

Jon, I got a heavy duty coupler for my Bravo to handle the 540 from Poodle. Not a bad price either. Might give him a shout if you are in the market.

[DonziJon]

I think I just figured it out. QUESTION: Will the retainer ring slip OVER the U-Joint..?

YES: IT WILL. You have to think about it. DJ