darin

I have a 98 baja with a 540 blower motor with a imco extreme drive. I broke three U joints last year and everytime it breaks it destroys the transom unit and the input shaft in the drive. I had a 540 blower motor in it in the past and never had a problem with it then I blew it up so I put a whole new motor in it last year same size but all new stuff. I put it in the water to test it everything was smooth no vibes no nothing. Cruising along and the U joint broke. I replaced the transom unit and fixed the drive. put it back in the water it was good for about two weeks and then it broke another U joint so a replaced the transom unit, fixed the drive, changed the bell housing and put a new coupler in. Everything was fine for about a month then out of the blue it broke again. So I was done for the season. Im trying to figure out what can be causing it to keep breaking. Any ideas ????

Smitty

iTrader: (1)

I think the alignment of the shaft is in correct. The only way you break a u-joint is by stressing it with too much of an angle.

Re check your alignment and heights to make sure they are all correct.

bajabob

i agree with smitty

darin

The second and third time I fixed it i checked it and had two other people from different marinas check it with alignment shafts and everything was lined up.

tommymonza

with your drive bolted on have some body big jump up and down on the cavitation plate while you look at the transom at the bottom of the boat and transom assembly.
My bet is there is not enough glass or there is rot down by the drain plug and when you hammer it the whole transom assembly is flexing in on the bottom and stressing your u-joints.

halfbuzzed

one more for the alignment

Tinkerer

Check for rear engine mount sag.
If the rear mounts sag you can still get the alignment tool to show proper alignment by lowering the front mounts. BUT the engine is NOT aligned and will blow couplers and U joints.

phragle

iTrader: (3)

how are thestringers? sounds like it might align but things are moving underway.

scarab31

Had the drive coupler replaced on my Powerquest when I still had it a few years ago. The marina never tightened the motor mount adjustment locking nuts. Idiots! Point is, make sure the engine isn't moving around if you are saying everything else is in check.

Mr Gadgets

When you checked alignment, did you rotate the motor over 180* and check it again. I had a coupler with a warped donut and it would move the engine 2-3" from side to side when I did the 180* thing. I borrowed a good coupler, lined up the motor and ran it for another 6-8yrs without a problem.
Your not forgetting the extended lock washers on top of the rear mounts are you? The go on top of the mount and under the bellhousing mount.. Or in between the two.
Can you watch the engine, transom while coming up on plane, that should reveal if there is any flex going on?? I would think.
What input shaft are you using, with or without grease fittings?
Which coupler did you use, the long snout or short snout, does the coupler side yoke have three orings or two? Or is that all new also?
There is something wrong, they should not be breaking that easy. Keep at it, there is something not right.

Dick