alpha alignment issue

[skipper2b]

Just so you know what your dealing with, I have 25 yrs of mechanical experience in several areas ,marine not being one of them. I have learned every thing I know right here and from my merc service manual. I bought my 3rd boat 3mo ago with a alpha one gen 2, the lower shift cable was stiff so pulled the od ,borrowed an alignment tool ,and it will barely start into the splines of the coupler so I couldnt even tell witch way to adjust. I took a new piece of 1 in round stock slid it in to the splines just to see the clearance inside the gimble bearing to determine witch way it needed to go . the up and down is fairly centered but shaft is off center to the port side about 1/4 in. when i turn the engine the shaft has about 1/8 in. run out at the bearing, back towards the center of the bearing, keep in mind that the 1 in. shaft fits fairly snug into the splines but not tight. note, the upper unit was replaced by po april of 2010 along with a new gimble bearing and i have the receipt from the dealer,I have to wonder if this alignment problem could be the reason. I dont have a problem with pulling the engine and replacing the coupler but Im not sure thats the problem.One more thing,the gimble bearing was driven in with a punch and the aluminum outer ring shows it but it feels good and I used the correct driver to make sure it was seated. Any advice would be appreciated,thanks

 

[Don S]

Re: alpha alignment issue

When you turned the engine 1/4 turn, did the alignment still show being off side to side?

 

[skipper2b]

Re: alpha alignment issue

yes, the shaft stayed to the left of center but changed slightly, this is a new piece of rod but its not a tool ,this may account for some of the run out . thanks

 

[Don S]

Re: alpha alignment issue

What engine?

 

[Bondo]

Re: alpha alignment issue

Ayuh,.... What motor,..??

How did We get from a stiff shift cable to the alignment bein' off,..??
What else has been done already, or not,..??
Do ya have any other history on it,..??

 

[skipper2b]

Re: alpha alignment issue

the engine is a 4.3, sorry cant make out the numbers. I did notice a slight whirling sound at low speed but it was barely noticable. I checked the alignment because I thought it should be done every time the od is removed. I have no other history than what ive stated. The boat runs and drives perfectly with no vibration and the od slid off with no problem . the splines look good but i have to wonder if the od slid off easy do to wear in the coupler splines. drive shaft and u-joints look like new.thanks again

 

[solar7647]

Re: alpha alignment issue

I once had an issue like that, the problem ended up the gimble bearing inner race got knocked out of center so every time I put the tool in it would hit the top of the coupler on the fly wheel. I Think I tweaked it when I pulled the drive out. It could be that. I would think that if the drive shaft was in there and then the tool would at least slide in some but if the bearing was messed up after drive removal it could of screwed it up. If that makes sense.

 

[Don S]

Re: alpha alignment issue

yes, the shaft stayed to the left of center but changed slightly, this is a new piece of rod but its not a tool ,this may account for some of the run out . thanks

Remove the lag bolts that hold the front motor mounts to the stringers. Then bump the engine left or right to get the alignment where it needs to be to get the alignment right. Re-lag the mount to the stringer tighten all down and recheck the alignment. Be sure to turn the crank 90, 180, and 270 degrees to make sure all is well.

 

[skipper2b]

Re: alpha alignment issue

Thanks for the advice Don, I'll do that tonight, and thanks to all who replied

 

[Brew2]

Re: alpha alignment issue

I'd definitely defer to Don/Bondo on anything related to your Mercruiser setup, however, I'll throw in my 2 cents because I recently had a similar problem with my frist alignment experience a few weeks ago.

I had virtually the same problem you describe (although my splines were slightly off vertically, not horizontal). Turned out I hadn't "whacked" the alignment tool firmly enough in all four directions prior to trying to test the alignment. Could barely get the tool into the splines, but after giving the tool a good whack up/down/left/right, it slid in effortlessly and only required a minor tweek to get the grease marks perfect.

Good luck!

 

[skipper2b]

Re: alpha alignment issue

Thanks Brew2, I did the bumping procedure several times but was concerned about the bearing outer ring being bunged up by the "mechanic" that installed the bearing and not letting the bearing center its self,but I was able to swivle the bearing in all directions with the alignment tool so Im confident with dons directions. I m just amazed that the boat runs so smooth with the alignment that far off,I guess the coupler is compensating for it.

 

[skipper2b]

Re: alpha alignment issue

update, had to move front of engine 3/4 in. to port and raise the front 3 turns of the nut. I know that sounds simple enough but it took me 8 hrs .so if anyone out there is dealing with this issue here's a little tip. the problem in my case was that the engine has been sitting in this pos. for 20yrs and the rubber in the rear mounts is very stiff so when I bumped the engine to the side it just came right back,so I took an old engine lifting hook and screwed it down to the floor beside the engine and connected a turnbuckle between the engine and the hook allowing me to pull the engine to the side untill alignment was achieved,then I pulled it about 1 1/2 turns more to compensate for some spring back after I bolted the mounts to the floor,that took several tries to get it perfect but its right on the money now. thanks to Don s and everyone who posted.