Gimbal bearing alignment

[Dsteve]

I have recently purchased a 1984 Sea Sprite with a 140 inline Mercruiser stern drive alpha 1 series. I always had outboards before and the stern drive is new to me. I only had the boat in the water twice before starting this repair. Both times out on the water I had a vibration and a growl at speed. The second time out I noticed water coming in the bilge. I suspected the bellows were leaking and maybe a bad bearing or u-joint. I pulled the drive unit and found the gimbal bearing and u-joint bellows dry but the bearing felt rough when I turned it by hand. The shift cable bellows was wet inside and the source of my leak I believe. I decided to replace all the bellows because they had taken quite a strong set from being left in the full tilt up position. I also replaced the gimbal bearing. I used a slide hammer to remove the old bearing. When the bearing came out I noticed that the center was out of alignment with the outer race by several degrees. I thought that the slide hammer had caused that. The replacement bearing was and still remains in alignment center to outer race. I used a steel collar which only contacted the outer edge of the race to drive the bearing in to the seat. I put a small mirror thru the bearing center to check that the bearing had met flush with the housing. I have reassembled the bellows per the manual using adhesive where needed the bell housing is in place. I have the proper engine alignment tool. Here is where my trouble begins. I can not for the life of me get the alignment tool to slide through the gimbal bearing and into the coupler. First I the thought the engine was just a little off. I tried to adjust the front mount. I cant get any where close to being able to push the alignment tool into the coupler. I got another bigger longer mirror out and and I have found the alignment tool and the coupler to be off center by about 3/16 of an inch. I rotated the engine and the coupler to alignment tool variance remains the same. My repair manual doesn't address this problem. Im really lost here. Does the gimbal bearing move enough to correct this problem? I have tried hammering on the alignment tool shaft. Although somewhat timidly. I haven't been able to move the bearing center race. To move the race off center must take some considerable force. And if the center race of the gimbal bearing is moved wont that prevent the inner seal from mating properly with the drive shaft? Any help would be much appreciated. Thanks

 

[Rick Stephens]

Gimbal bearings gimbal. Which means they can swivel. You can eyeball the gimbal to aim it to the coupler, use your bar to crank it in line. Once you can start the bar into the coupler, slide it in and rap the alignment bar fairly sharply with a 2 pound hammer up, down, left and right. That will get it closest to centered. Then you can start checking/setting the alignment.

Rick

 

[scoflaw]

1" wood dowel inserted into the coupler will give you a good idea which way the gimbal needs to move. if you have trouble with the bar.

 

[Bt Doctur]

And if you are off by that much its a good bet the rear motor mounts are collapsed.

 

[harleyman1975]

Could be some reconstructive surgery in your future.

 

[Dsteve]

Thanks for all your advise. "Gimbal bearings gimbal", was a huge help. I didnt realize it would move. I Had to really crank on the bearing to get it to move. In fact I used a 5 foot cheater pipe on the end of the alignment bar to get enough leverage to move the bearing. With enough pressure it finally cracked loudly and moved. After a few adjusting whacks on the alignment bar it slipped into the coupler. However Im still struggling with the pressure reading in the grease track on the alignment bar. The alignment bar does slip into the coupler easily but for some reason i get a hard track on the starboard side and a bit of a zipper sound, which I believe are the splines rubbing the mill marks or lathe marks on the alignment bar. I have rotated the engine to check the coupler for out of round but the track remains the same, always harder on the starboard side of the bar. I have tried hitting the bar left, right, top and bottom. That has either made it not align at all or I get back to the same results hard tracking on the starboard side. The top bottom and port side grease track is lighter. I have moved the front mount up and down i didnt expect that to change my side tracking and it did not change it. Any suggestions? Thanks again to all of you for your input.

 

[wellcraft-classic210]

I have used a piece of 1.00 inch diameter aluminum stock to visually see whats going on. Inserted into the engine coupler you can see if the motor angle is off. Be sure to rotate the engine and check every 90 degrees or so.

Its not uncommon to for it not to be perfect & have some runout. Getting it as close as you can is generally good enough.

 

[bspeth]

If it slides in easily with the engine rotated through 3,6,9,12 oclock you are good to go,dont worry about the grease.If it is too tight for your liking then loosen the front mounts and lift the front of the engine with the eye or sling the water pump,IMO it is way easier than getting in and out of the boat a hundred times.I have been there.Hopefully you did not mash the coupler splines when you hammered on you bar ,an inspection is in order.

 

[Dsteve]

I left this project sit for awhile. I then decided to attempt the gimbal adjustment one more time. I rechecked the spline area ,cleaned out the spline area and checked for any damage. It all looked good. I had been getting a strong grease track on the starboard side of the alignment tool and a zipper sound during insertion. I reinserted the alignment tool until it bottomed out. I hit the side, of the shaft of the tool, with a 2 pound hammer up down and side to side i had to do it a couple times before the bearing moved to a more centered position. I readjusted the front mount again. I got the best fit and grease track I could. Still had a little zipper sound but much much less so. The bar never did move in or out without some resistance. But I put the drive on anyway. That is when I felt i really had a good alignment.The drive slide on all the way smooth and very easily. The only resistance I encountered was when the BA o ring between the drive and the bell housing slipped off and caught the bell housing tab. After I recentered the oring the drive slipped into place and bottomed out very easily. Thanks again for everyone who replied to my question. It has been really nice to have the help and advise.