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DLewis
06-10-2008, 11:31 AM
In doing some routine work, I discovered that the prop shaft coupler bolts were loose. The prop shaft to the V-drive had 4 bolts (with nylocks) but it appears that I may be missing a few - as the coupler is drilled for maybe 8 bolts (?) As I rotated the prop shaft, the bolt that happen to be at the 12 o'clock position would not wiggle. As I rotated the prop shaft the bolt then became free and had some play (as though it needed to be tightened. I have read some threads about prop shaft alignment - and am guessing that I need to do this (?) The boat runs out smooth and I have never felt any vibration. Anyone have any ideas on what I need to do? Leave it alone or adjust the prop shaft coupler? Thanks for any help.

DLewis
06-12-2008, 01:58 PM
I found several old posts from this and a few other websites. One item not mentioned in any post is the how tight to make the 4 bolts that mate the prop shaft flange to the vdrive coupler.

Anyone?

CPlane Pilot
06-12-2008, 02:17 PM
I'm not sure if Mastercraft has a spec on it; however, typically, a 3/8 stainless bolt would be torqued to 19 ft/lbs

jrhollow
06-12-2008, 02:24 PM
Like you, I didn't have any vibration, but my strut bushing was wearing unevenly. You need to realign you engine and put new bolts in the coupler. It's not that hard to do, just takes a little patience.

I suggest using a mini piston jack to more the engine around.

Laurel_Lake_Skier
06-12-2008, 02:30 PM
If you had a direct drive I 'd say that you should get the alignment done and I don't know why the V-drive would be any different. The two flanges, one on the drive shaft and one on the transmission, must be lined up parallel with each other. For the direct drives .003" (about the thickness of a sheet of paper) is the spec. for amount of gap difference around the faces of the two halves that bolt together. The spacing is checked with a feeler gauge. If the alignment is off, and it sounds like yours must be if the bolts go from tight to loose, the engine/transmission are moved on their mounts until the two flanges are within .003 of parallel to each other. There is no adjusting of the flanges themselves.

ttu
06-12-2008, 02:32 PM
here you go.

DLewis
06-12-2008, 09:36 PM
Thanks TTU - One item that I am still uncertain is - do I need to loosen the big brass nut (Jam nut ?) before the prop shaft will slide back and foruth?

Tom023
06-12-2008, 11:09 PM
Thanks TTU - One item that I am still uncertain is - do I need to loosen the big brass nut (Jam nut ?) before the prop shaft will slide back and foruth?

No, the coupler and shaft will move as one piece with the nut tight. You only need to remove the nut if you want to pull the shaft from the coupler and this generally requires a shaft puller / slide hammer.