Mercruiser alignment issues

[Rick Stephens]

Same setup I have. No problem whacking more on a bearing with that tool..

 

[achris]

ok, that looks like it applies the load to the bearing outer, which doesn't destroy the bearing... Most people don't have the accessories with the alignment bar.

Chris........

 

[tigger3650]

Whew! You all had me worried for a minute! Getting down to the wire on this. The 29th is approaching fast and I still have to work!

 

[alldodge]

The boat is an '85, the motor came out of a' 90'sish Bayliner.

Lets clarify the before and after. Which type coupler is installed and what drive?
The link below shows the 2 types of couplers

http://www.mercruiserparts.com/bam/subassembly/30893/963/300

 

[tigger3650]

I looked at the two types. I think I have the one with the triangle backing plate.

If I look behind the motor I can see a small shaft with a grease fitting going from the motor to the transom assembly.

I don't see a shaft protruding or a grease fitting on pictures of the round style.

I did notice on pictures of replacement couplers (triangle type), some come with a drive shaft that has spots for 3 O-rings. mine only has 2 spots for O-rings however, I did measure it and it is the longer shaft 9 9/16".

 

[tigger3650]

Other than being about $350, how painful is it to replace the coupler?

Is the coupler even the problem?

2 days ago, I had the motor perfectly aligned all through the rotation. Yesterday it feels like it is off. I could get it close at one position, rotate the motor and it would be really tight again.

I have held a bar on the end of the coupler while the motor is running (being very careful not to hit the grease fitting or anything else for that matter) and the bar doesn't even vibrate much less bounce as you would expect from a shaft being out of round.

 

[Rick Stephens]

I don't know either, but one thing common to coupler issues, they don't fix themselves and then go out of round and then fix themselves, and then go out of round again. I really doubt that's the problem. If you were to decide and replace it, it requires at minimum disconnecting everything and then pulling the motor up and forward enough to remove the flywheel cover to access the coupler. The actual coupler replacement is easy peasy. Hard part is lifting the motor.

How do the spline marks on the alignment bar look when you are in alignment?
Did you successfully get the u-joints replaced?
Is it possible the rear motor mount washer stacks were not done correctly when the motor was installed?
Are we sure the rear motor mount bolts are tight?

 

[tigger3650]

I'm going to give the alignment another round tonight and check the rear mount bolts. Not sure after that

 

[achris]

You have the new style coupler and an old style input yoke. You need to replace the yoke with the shorter one.

 

[alldodge]

You have the new style coupler and an old style input yoke. You need to replace the yoke with the shorter one.

OK I'm puzzled again (doesn't take much these days), I sure your right but:

My manual 6 says the shorter input shaft is the older style and is used with the older coupler. The longer shaft is used with the newer Tiangle coupler

 

[tigger3650]

OK, now I'm confused. Do I continue searching for a another shaft?

 

[Rick Stephens]

I don't know enough to show my rear by disagreeing with achris, who has worked on more sterndrives professionally than I have ever been near. I thought the drive shaft length was the same for all Alpha 1 drives and only changed with introduction of Alpha 1 from IR-IMR model update. You started with an Alpha 1 and updated to a newer motor. You still have an Alpha 1 outdrive. I could be missing that there are differences in couplers that I am totally ignorant of. So I frankly don't know what is the correct answer.

 

[achris]

Rick, you have this one. Brain-fart time. Longer shaft for later models. (in defense, it was late at night, and I was on my phone posting :facepalm Yeah, I know, pretty weak....

 

[alldodge]

It's all good, just getting the post count up

 

[tigger3650]

Ok, so I am guessing we have ruled out the improper shaft length.

On a good note, I went back at it today. It took me roughly 20 minutes, by myself, climbing in and out after each turn, but I got the motor aligned perfectly. I kind of strayed away from the whacking all 4 sides of the bar at first and just used some good old fashion elbow grease and leverage and tried to move the bearing angle specific to where I "thought" it should be. I did this about 3 times before it felt right and started adjusting the motor. Got it nice and smooth, then bumped the starter. I colored one of the bolts on the pulley so I could keep track of the crank position. First 90deg and it was a little stiff but I was able to adjust it out. Checked at the rest of the cardinal headings and it was smooth throughout with even grease marks. I tightened everything up (including checking the aft mounts before I started) and then rechecked the alignment. Fought a little to get the drive back on but it was because I was by myself, and the splines were off a bit and I played hell trying to turn the shaft without the prop on it. Once I was able to twist it a little bit, the drive slipped on. Tomorrow I will fire it up and pray to the boat Gods that my rattle is gone.

More to follow tomorrow.

 

[tigger3650]

Ran it up this evening and the rattle is still there. Here are some pictures of my setup and I stuffed my hand behind the motor and tried to capture the coupler. I will also post a video here soon of the rattle. I pulled the top cover off the drive and other than the oil due for a change, everything looks good.

​​​​​​​I'm not sure what to do from here, and my Keys trip is approaching fast and none of the mechanics around here can look at it for at least 3 weeks.

 

[tigger3650]

I wasn't able to upload the pics or video, try this link and see if it works.

 

[tigger3650]

I just read a note in the manual again, an it states there should be an 1/8" gap in the bore behind the bearing. I'm guessing this is "aft" of the bearing and not between the bearing and the motor. I'm going to pull the drive again tomorrow and double check this.

I may need a bigger hammer for the bearing driver

:facepalm::mad-new::frusty::mad2:

 

[alldodge]

I don't see it being the bearing unless you have roughness.

Thought you said you have a 90ish motor, and the triangle coupler, this doesn't look like the triangle coupler

 

[nola mike]

Have you run it with the outdrive off?