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SinclairMobius
07-20-2009, 02:00 PM
2005 Mobius LSV.

Was out this weekend with a bunch of wakeboards, about the third wakeboarder I put the tranny into gear and ... no movement, just revving.

Checked the electrical connections to the throttle, the mechanical connections to the tranny, no joy.

Finally looked down at the prop shaft and saw three of the four bolts sticking out of the flange on the prop shaft with no nuts on them, still haven't found the fourth bolt. Prop shaft was floored to the packing seal.

Called the marina and was asked if I hit something. I said about two years ago and replaced the damaged prop. They said it probably caused the shaft to be out of alignment and caused the loosening of the bolts that mount the shaft to the tranny.

They recommended I bring it in for realignment and rebolting. For a lot of reasons, i decided to do it myself, so here's the story:

Bolts - get schedule 8, 3/8 2 1/4 bolts with nylon lock nuts at hardware - they only had 2 1/2 so had to settle for lock washers (2 on each bolt) to keep the longer bolts from striking the tranny.

Tried to reseat the prop shaft to the tranny - off by 1/16 vertically. The cup on the prop shaft wouldn't even seat in the tranny. Loosened the two lock nuts on the bow facing port and starboard engine mounts, marked the top of the nuts with a sharpie to know how much I turned them. Turned both 1 turn (16 threads per inch bolts) and that allowed the shaft to seat. Checked with a feeler gauge all around and had near perfect mating even after turning prop through 360 degrees.

Relocked the engine mounts, put the four new bolts in (pain in the neck to tighten - cramped area). Put paint on the lock nuts because they protruded over the flange by about 1/32 - afraid they would rub the tranny housing. Sea tested with full power reverse / forward. No paint rubbed off - clearance good. No vibrations. Seating good.

Will inspect bolts again in another week to ensure tightness.

Crazy that all four bolts WITH lock nuts on them would work loose, but they did.

wolfeman131
07-20-2009, 02:09 PM
Glad you were able to get it fixed. Does seem a strange situation & I'm curious how it all happened.

Are you on Lake Sinclair in Milledgeville, GA? If so, where do you spend your time and what does your boat look like?

ftd
07-20-2009, 02:09 PM
I had this exact same thing happen on my Boomerang. Replaced nuts with Nylocks. Years later and they haven't loosened again.

Frank

SinclairMobius
07-20-2009, 04:01 PM
wolfeman131 - Lake sinclair has a lot of flotsam in the spring - 2 years ago hit some floating debris and bent the heck out of a couple of my prob blades.

Replaced the prop thinking all was good. Didn't notice any vibration since.

Trying to remember if lately i would hear a "thunk" when i switched between forward / reverse, but can't recall.

Still haven't found the fourth bolt in the bilge - might still be there or if there never was one, could have been part of the problem.

I live right by the power plant on the finger of land that's between the warm water effluent cove and the main channel on the main channel side.

I have a 2005 Mobius LSV - White on black hull with 4 black tower speakers. I'll post up a pic as soon as I can. New to the board.

wolfeman131
07-20-2009, 05:19 PM
I live right by the power plant on the finger of land that's between the warm water effluent cove and the main channel on the main channel side.

I have a 2005 Mobius LSV - White on black hull with 4 black tower speakers. I'll post up a pic as soon as I can. New to the board.

Dang! You just missed our mini-jam 2 weeks ago! Check out the pics under the Moomba Families section. I'm up on Island Creek and have a Brittany Blue Outback V w/ a Monster Cargo bimini.