Prop Shaft Alignment Yearly Maintenance Item

[chester]

Thanks docdrs, wetting the strut did the trick. Wiggled the shaft up and checked it while turning the prop, and could never fit a .0025 gauge in. Surprised it was that tight everywhere while turning it but I'm not gonna complain.


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[zd215]

After having some vibrations and noticing the prop shaft coupling bolts were loose, I decided it was time to check the alignment.

The feeler gauge keeps telling me the coupling is tight at the 12 o'clock position, bolts are still in but very loose. I started lowering the front of the engine, turned both bolts about 6 times each and couldn't really tell a difference. By 6 turns I was beginning to bottom out on the mount, so I stopped.

My next move was to start raising the engine from the rear but discovered I didn't have the right size wrench for the rear jam nuts. Tomorrow I will be picking up some bigger wrenches and trying again. It also looked like the rear mounts were being stressed from lowering the front so much. Should I loosen the bolts holding the trunnion pins so they can rotate?

6 turns seems like a lot of adjustment (about an inch vertical?), does this sound right? Should I completely remove the 4 bolts from the prop shaft coupling to check where the 'natural' position is?

Oh, and for others wondering, you need a 15/16 wrench for the front mounts.
Any idea what size i need for the rear?

[zd215]

Today I moved the engine up and down again with the prop shaft completely disconnected and saw how quickly it comes out of alignment. I still couldn't produce a gap at the 12 o'clock position at all, the gap at the bottom remained at about .013-.014. The prop shaft does not appear to be bent since the gap and lack thereof remained in the same locations as I rotated the shaft.

I ended up putting it all back where I started and bolting it back together.

Any tips for my next try?

[DOCDRS]

you have to make sure your engine rubber mounts have not deformed as well . As long as you can rotate the shaft 180 and get the same gap then you need to keep going. You need to have the bolts in loose to get a true alignment , just keep pulling the flanges together to measure. The major thing here is to be able to visualize in your head what you are trying to accomplish.

[Darter]

Got mine done today. Had to raise the front about 7/8ths of a turn and got it to ,0025" or so all around. My first shot at it and I was working in the hot sun so I wasn't especially nitpicky. Will dial it in more next season.

Thanks for the great writeup!

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[James Johnson]

Hi, i am about to adjust my drive shaft alignment after replacing it. Great post on how to do it, THANKS
Jim

[James Johnson]

About to do mine, Excellent post

[Hayden]

I'm planning to do this in the spring. I've read through all the posts and have a general idea of what needs to be done.

I searched for some videos on "Moomba / V drive shaft alignment" but most of what I found was for larger boats. Has anyone on this forum seen a video doing step by step on a Moomba?

[scottk1826]

Hayden, if you find a video for a V-drive prop shaft alignment, please post the link here because I can’t see any of the pictures in the earlier posts. I completely removed the coupling bolts from the flanges and I don’t have any space between the couplings at any point. And to make sure the two couplings weren’t rusted together, I turned the prop shaft which turned the prop shaft coupling while the V-drive coupling remained stationary. Still no gap anywhere between them. So either mine is perfect or I still don’t understand what I am checking, even after reading this post twice and reading one of the links in one of the replies. I have a 2016 Moomba Craz. Thanks! Scotts

[DOCDRS]

If the cutlass bearing is dry it can prevent aft movement of the shaft flange. wet the bearing and turn the prop and pull it back n forward a bit to free it. But just a 1/4 inch is all you need