Drive Shaft snapped

[justgary]

I installed the new drive shaft, but I could not get the alignment 100%. I am just not sure which nuts to turn which way and how far. I have about a .010 gap at the top. I literally worked on it 3 different days.

I sent the prop to OJ and they said the hub was damaged and it was unrepairable. I test drove the boat today and had a bad vibration off idle, so my backup prop (previously repaired) is out of balance, I need a new strut, or I bent the new shaft tweaking the motor mounts too far. I have new vesconite? bushings on the way in the next day or so.

It is very unlikely that your strut is causing a vertical error since it can't really bend in that axis. Also, you can't bend your shaft if you are adjusting the motor mounts with the coupler loose.

To close a gap at the top of the coupler, the front of the motor needs to come up. That one is much easier to do delicately than a side error. Loosen the two top nuts on the motor mounts a few turns, then use the bottom nuts to jack the engine up by "loosening" them also. You may need a full turn or two to get the alignment in with a gap that big. Make sure that the two coupler halves are concentric also, since just being parallel isn't good enough. That would require moving all four mounts the same direction to correct.

[skiatook_bu]

I used the greenman "wire indicator" today and the prop fins varied by 1/4 inch. I had a new prop overnighted which will be here in the morning. Maybe my repaired standby prop has been out of whack the whole time.

I bottomed out the motor mounts to where the engine was sitting on the the coupler and the shaft would not turn. Then I noticed the instructions I was reading were for a direct drive. So I had the drive shaft crunched under the engine in the log.

Right now I can turn the shaft by hand with the prop off. It turns pretty freely. I am going to tackle the alignment again in the morning. (attempt #4)

The whole thing is rather complex. You don't have to answer this, but is the front motor mount the front of the engine which is backwards or the one closest to the front of the boat. Moving the (rear of the boat) mount up makes the coupler go down because it pivots on the other mount. Opposite for the other one, up is up, down is down. Then one set of nuts raises, while the other set lowers turning them in the same direction. Because of the pivot points, one mount moves things almost twice as fast as the other mount with the same number of turns on the nut. One side of the boat, you move the wrench toward the back of the boat, the other side you move it towards the front. That not even covering where to stick a pry bar to move things side to side.

You would think these numbers would be calculatable in a spreadsheet or chart. Enter your top gap/bottom gap, look at the chart crank the engine mounts clockwise 4 turns, crank the vdrive mount counterclockwise 2.5 turns and be done.

I ended up drawing a mockup graphic and moving things around in the computer to figure out what mounts did what to the coupler. I will post it all on here when I am done. It will hopefully make it clearer to others in the same dilemma.

[justgary]

By jove, I think he's got it!

[malibu2004]

I PM'd you with my number if you want to give me a call I can help you if you have any questions.

[85 Barefoot]

Look at the crusader engine manuals on pcm's website. Their mounts are proprietary as I understand it but they have "instructions" for what needs to go up or down depending on where the shaft is in relation to the coupler. Until you have it aligned, you should not be driving it. The shaft hole is irrelevant a sto whether the shaft is dead in the middle or not. One of the strut bolts looks bent to me.

[skiatook_bu]

I received a new prop on Friday and finished aligning the engine. I got it to pinch the .003 feeler gauge on all sides. Test drove it Friday night after dark and all was good. Dropped the boat in on Saturday, watched the fireworks on the water. Sunday we were out from sun up to sun down.

Thanks for all the help!

Edited July 6, 2015 by skiatook_bu

[GreenMan]

Glad you were able to work through it and get it sorted.

One of the advantages from the whole exercise is you know a lot more about your boat and are probably more confident about tackling things in future.

Now, ENJOY!!!

[ande2407]

Crazy world. Your photos look exactly like what happened to mine yesterday. Shaft separated in the same spot. I'm just starting to research how to begin, but I think it is going to be a spring project and just winterize it. Been a rough summer for the boat.

If you ended up with the drawing for what to adjust for what, I'd love to see it!

[skiatook_bu]

I need to write up the full instructions, but this will probably help you.

Link to PDF file:

http://bit.ly/vdrive-alignment

Edited September 1, 2015 by skiatook_bu