Gimbal bearing replacement and engine alignment

[tcschweitzer]

After doing some research online I decided to rent a bearing puller and an alignment bar and replace my gimbal bearing on my 94 Crownline 4.3L alpha one gen II. The bearing had been making noise for months so I knew it was time. The outdrive came off easily albeit being much heavier than expected. I noticed water in the bell housing which I believe is from the idiot mechanic I took the boat to 2 seasons ago to replace the bellows. It seems he forgot to replace the water intake O ring. I'm assuming that's what ruined my bearing. Anyway, the bearing came out easily, the u joints look great, and the outdrive seems to be in good shape. After watching some videos online I manufactured a piece of wood to press the bearing back in and I really thought i'd have the boat in the lake by happy hour. That's when my issues started. I could not get the outdrive back on. It stopped about 1.5 inches short of going back on. I fought with it for hours. I used a mallet to start "persuading" it to go back on but something told me not to force it. I was right, just a few hits from a mallet required tow straps and a ratchet to remove it. Thankfully I didn't damage the splines. I figured out this was an alignment issue and my alignment tool wasn't going in all the way. I couldn't even get the alignment tool to bottom out. Well, now I started tackling the motor mounts to start aligning the engine. After disassembling the rear upholstery to get to the motor mounts I found them rusted and stuck. A few hours with a breaker bar and some blaster I got them loose. I'm actually surprised I didn't break them.

The first thing that I noticed about my motor mounts was that the port mount was easily 1/4-1/2 inch higher than the starboard. I attributed that to uneven stringers however the more I thought about it the more it didn't make sense. Crownline makes quality boats and i'm sure the stringers weren't that far off. I also noticed the port mount looked newer than the starboard. I'm the second owner of the boat and have done no mount replacements but who knows when the other guy did. I started adjusting the mounts up and down for hours and still couldn't get the darn alignment tool to bottom out!. Frantic I started researching and found out that the alignment tool is also used to align the gimbal bearing (wish someone would have told me that). It stated, tap the tool with a mallet on all 4 sides and BINGO the alignment tool slid about 9/10 of the way in and got stuck. It took all my strength to get it back out. So now i'm cursing up a storm because i've spent the last 5 hours messing with motor mounts and I probably just needed to align the gimbal bearing. Now that I've jacked up the mounts it will take hours probably to re-align it.

So, here's my question, now that I have to realign the engine AND the bearing, is there a reason to consider the original placement of the front motor mounts? They were obviously not level. Would there be a good reason for that? Shouldn't an engine be level? How do I level an engine in a boat that naturally lists to the port when in the water and on land is never on level ground? Should I try to align the engine keeping both motor mounts even?

My gut instinct is to try and align the engine with the front motor mounts even, however, someone at some point raised the port side. Why would they do this? Any insight is appreciated.

 

[dozerII]

There is a whole bunch of info here. http://forums.iboats.com/forum/engi...es-outdrives/455000-engine-alignment-how-to-s

You will most likley have to use the lifting eye above the thermostat housing to hang the motor to get the motor back to level then proceed with your alignment.

 

[tpenfield]

There could be some reasons why the engine mounts appeared to be uneven . . . the transom opening (keyhole) could have been misaligned or the stringers may in fact be a slight bit off. Basically the transom assembly determines the reference point and everything else should be on the same 'plane'.

I am not sure of a good way to check the level of the transom assembly (with the engine still in the boat), but you may want to take a look at the outdrive from the exterior to see if it looks perpendicular to the ground when the boat is level.

You could then lift the engine from the lifting eye, which is usually around the thermostat housing and see where the front mounts want to be (even or uneven).

Your engine was probably aligned previously, but since you adjusted it, you may as well start from scratch.

 

[revkev6]

after having done basically the same thing you are doing now a couple weeks back.... here is what I would do.

1 put the motor back where it was originally and start there.

2 try to align the motor and see how it goes. It sounds like you haven't read up on the alignment much based on what you did originally.

3 put a thin layer of grease on the alignment bar

4 slide it into the splines on the coupler.

5 now heres a tip that NOBODY tells you... the gimbol bearing moves and can bind the shaft. to get the gimbol bearing to better align with coupler once you have it in as far as it will go take a small 3 lb sledge and give the alignment bar a few taps all the way around. left, right, top, bottom, NEVER tap it in. slide it out, slide it back in and repeat.

6 reapply the grease on the alignment bar and reinsert. pull it out straight and even without touching anything! the marks from the splines will tell you which way the motor needs to go. if the splines mark heavily on top but no spline marks on the bottom then the front of the motor needs to go down, if they mark on the bottom the motor needs to go up.

once you make an adjustment (I did about 1 turn at a time) put the bar back in and repeat steps 4-6. once you have an even spline marking and the bar slides all the way in and out easily you will be good.

I watched videos and read a couple tutorials before I tried it and nobody told me it's ok to move the gimbol! I spent about 3 hours trying to get the shaft into the spline without moving the bearing itself! this was a motor replacement after replacing the floor and stringers so we thought everything was out of wack. ended up we had it almost perfect right from the start but just needed to bump that gimbol bearing around until it lined up nice and smooth!

 

[bspeth]

Do your alignment with the lifting eye.It is BY FAR the easiest way,especially since you don't know where you are at regarding your starting point.Dont waste your time turning those nuts 1/4 at a time and hoping to get lucky.

 

[Benny67]

I just went through the same thing. Revkev6's advice sounds like the way to go.

What I found worked for me was pushing the alignment bar in just partially and moving it up and down and left and right a few times and then kinda feel my way around pushing and feeling the bar while you try to slide it in (gently). Think of your first time...well, you get the idea.

Once you feel it go all the way in I would do the grease thing to check and see how off you are on the alignment itself.

You could also slide a long 1" wooden dowel in the shaft hole in the motor and try to eye it up with the center of the gimble bearing just to get you can get a visual on how off you knocked the motor out of alignment.

If you see the wooden dowel is cocked in any other direction other than being centered in the bearing you could get a rough idea on how to adjust the motor.

 

[tcschweitzer]

Thanks for all the advice. I didn't have time to build an a-frame to adjust the engine from above so I leveled it a quarter turn at a time. Took me about 2 hours. The motor was actually out of alignment. The motor needed to adjust upward about a 1/16-1/8 of an inch. I'm assuming this is fairly standard on a 20 year old boat that's running with an original gimbal bearing. Interestingly enough the port mount (which was previously lower than the starboard) needed more adjustment than the other. The port mount was also the most rusted and stuck. My theory is that the idiot mechanic that changed the bellows a few years ago saw the alignment problem and used the starboard motor mount to compensate. It turned much easier and was not rusted. The motor mounts are even now.

As stated by revkev6 and benny67, the thing NO ONE TELLS YOU is that every time you make a motor adjustment you also need to bump the alignment tool up down left right gently to align the gimbal bearing. This made all the difference. The outdrive slid in smoothly and without effort (other than supporting 100lbs with greasy hands and trying not to damage the gasket).

I'm glad I went through this 3 day exercise, I learned some valuable lessons, knocked some rust off the motor mounts and could probably do a bearing in an afternoon knowing what I do now.

Some tips for other people that may being tackling a gimbal bearing for the first time

1) This job will take you 2-3 full days the first time

2) Rent the proper tools ahead of time. You absolutely MUST HAVE a bearing puller, you can rent tools for free from autozone and Oreilly. You need a slide hammer bearing puller with the rear axle attachment. Do not get a pilot puller, it will not work. You MUST rent or buy an alignment tool. It's almost impossible to do this without one. My marine store rented me one for $10 a day.

3) Make sure you purchase 2 replacement gaskets for the outdrive and orings for the water uptake connection. You will damage the first one and lose your oring.

4) Make sure you place the boat in forward gear. Here's another thing no one tells you. When you put the boat in forward gear, push the throttle all the way down and lock the gears. This done by turning the prop CCW about a quarter turn. This ensures the shift linkage will match up when reinstalling the outdrive.

5) The outdrive is heavier than you think. Take the prop off first (especially if SS). Build a stand if necessary or use a motorcycle jack to help

6) Most people advise to tie the trim rams up so they are out of the way. I actually removed both the front and rear pins and let them hang (not by the hydraulic lines! Mine had stainless hangers included), but both methods would work.

7) When pressing the bearing in I used a notched piece of a 2x4 that I made in about 5 minutes. It worked great. After you press the bearing in don't forget to replace the grease fitting with the set screw provided with the bearing. New Gimbal bearings for alpha one's are sealed and the set screw is used to plug the hole where the original grease fitting was.

8) Once you get the bearing in take the alignment tool and lightly grease, insert it through the bearing and gently push until you feel it stop. Most likely the tool will stop before it enters the receiver. Take a rubber mallet and tap the alignment tool firmly on the top, left, right, and bottom. Now you should feel the tool slide in. If it bottoms out without any effort you are lucky and don't need to align your engine. If it takes more than a few taps, you need an alignment. There are many good forums and youtube videos about aligning. At this time, hit both front motor mounts with PB Blaster and call it a day. Your next day will be filled with cursing, contortionism and breaker bars. There are many resources about how to do this correctly and i'm not an expert. My only advice is every time you make a motor adjustment, whether that's using the mounts or an engine lift, you need to adjust the gimbal bearing by tapping up down left right and then checking alignment.

9) Now that you're aligned, time to put the lower unit back on. Before going any further, make sure your gasket is on and the water uptake oring is in place with some heavy grease so it doesn't fall off. Its much easier with 2 people. It's hard to get the drive shaft through the hole and gimbal bearing while supporting 100 lbs of dead weight with greasy hands. You also need to turn the prop or drive shaft CCW to align the splines while supporting the drive. DONT TURN IT THE WRONG WAY OR LET THE PROP TURN CW. You will have to take it back off and relock the drive in gear. One other thing, before putting the outdrive back on, put the boat in neutral and then put it back in gear, pressing the throttle all the way down. This will make sure the shifting mechanism is lined up. Now that you've attempted this by yourself and ripped your gasket and lost your oring, go get your neighbor and try again.

10) hopefully the outdrive went on smoothly. If not, take it back off and try to align the gimbal bearing using the alignment tool. If his doesn't work, time to realign the engine again. This can be a painstaking process.

Thanks for everyone's advise. Boats going in the water tomorrow and hopefully will run smooth! I'll keep you posted.