smokin' gun

2 things cause this loose front mounts or the coupler not being greased properly just think how many times you trim the drive up and down thats how many times the shaft goes in and out of that coupler sort of like a saw the splines in the coupler are made of aluminum and shaft is made of steel dont be afraid to use a lot of spline grease on that shaft either also you said front mounts were loose im assuming your referring to the 2 big nuts get yourself an alignment bar that motor has to be realined now any mercruiser dealer should have 1 or you can buy them for about a 100.00 bucks shaft should slide in and out threw gimble brng freely good luck

switzer master

got the new coupler in there and i'm having trouble lining up the motor, whats the best way to get the shaft to go in smooth. I have the alignment tool from a local shop, does the back two bolts have to be shimmed? thanks

excursion

No, the back two bolts are to be thightened down all the way. You should have a lock washer and a canvas washer. That will hold the motor in correct location for the rear. Take the motor lift and hook it to the front of the motor and raise it up or down until the alignment tool goes in and out smooth. You might have to adjust the front mounts.

scarab31

Been there, done that in my '98 Powerquest 260 with a 502 and Bravo drive. Coupler. $1000 repair all said and done.

switzer master

got it done, was alot of effort, had to brace up my garage attic to support the motor, used a chain fall to pull it up. took a while to get the motor adjustments right, to get the tool to slide in and out smoothly. had to put two small washers on the back two bolts to get it to line up, its perfect now. going to take the boat to the local shop and have them pump the out drive up full of lube and i'll be on the water tommorow, thanks for all the advise, this site is great

hoozeyurdaddy

just a little info and it sounds a little late, But, If you had to add washers to the rear mounts other than the stock fiber washer and spring washer then there is a problem and something has moved that souldn't have. I would watch it close and check the alignment again in 5-10 hrs so it don't cost you another coupler.

excursion

That is what I have already told him, nothing else should be in the back except, spring washer and fiber washer. He needs to move the front of the motor to re-align the input shaft.

switzer master

the motor sat to low without those washers, and the tool wouldn't go thru, I tried moving the motor up and down on motor mounts and ended up keeping the motor as far down as the mounts would allow me, the tool did slide in and out smooth after that, i have put about 7-8 hrs on boat since the repair and it feels ok, the boat has a little more vibration than b4, boat shop advised that it was normal because of how tight everything is now, thanks for the tips, I'll recheck that alighnment in a few days

Mr Gadgets

switzer,
Hoozyurdaddy is correct. If anything other than the stock lock washer and fiber washer are used then something is a miss. The lock washer is kind of a double lock washer. And the Fiber washer goes around it. If you have the back of the motor up or down from that set reference point that Merc built into the transome setup, then it isnt correct. You should double check it. I know it is alot of work, but I have seen broken input shafts and couplers..
Another thing I do when aligning it is to get it set right, then roll the motor over 180*. I had a coupler that the inside was warped.. when I rolled the motor over the alignment changed. Took me a while to figure it out, but I did. Then I borrowed a good coupler, aligned the motor and made solid mounts and reinstalled the old coupler. Ran that coupler with 690hp for several years..

Good luck with it.

D*ck

switzer master

these washers im using are about 1/8 inch thick, i'm going to recheck the alighnment b4 I take it out again, if the coupler is out of round then that may explain a slight aditional vibration, and the need for washers, how tight should those back bolts be?