Drive install.... how tight is too tight?

bigskiohio

Master Chief Petty Officer
Joined
May 3, 2008
Messages
882
Re: Drive install.... how tight is too tight?

As I understand how it works, you have three different diameter shafts on the alignment tool: The smallest is sized to fit precisely the diameter of the coupler, the next largest is sized to pass easily through the bearing with room to spare, and is long enough so that the smaller diameter shaft can engage the coupler and slide part way in, the larger diameter shaft is sized to precisely fit in the bearing. .

now that you said it that sounds right that the largest diameter goes in the bearing .
 

300sflyer

Chief Petty Officer
Joined
Jan 1, 2009
Messages
627
Re: Drive install.... how tight is too tight?

Well, I raised the front engine mounts by nearly an inch each and am running out of thread. However I have almost no change on the alignment tool. It still goes in the same distance. Ugh, what am I missing?

Raising the front of the engine one inch, should have made a huge difference. Are the grease marks on the bar still the same or have they changed? I'm thinking you went too far... A half turn of the nuts can make a difference.
 

Knot Waiting

Senior Chief Petty Officer
Joined
Jun 23, 2006
Messages
761
Re: Drive install.... how tight is too tight?

Raising the front of the engine one inch, should have made a huge difference. Are the grease marks on the bar still the same or have they changed? I'm thinking you went too far... A half turn of the nuts can make a difference.

Back at it again today. I cant really tell if the marks changed much, I did notice that with the engine at its highest point the tool got stuc easiser. Im gonna lower it back down some. Im using a digital caliper to gauge the distance between the mounts so that I raise it evenly.
 

bigskiohio

Master Chief Petty Officer
Joined
May 3, 2008
Messages
882
Re: Drive install.... how tight is too tight?

did you set the gimble bearing?
 

ken_23434

Petty Officer 1st Class
Joined
Jul 28, 2008
Messages
313
Re: Drive install.... how tight is too tight?

did you set the gimble bearing?

By that, he means to put the alignment tool in place and then lift on the alignment tool, press down on it, pull it to the left and the right (all directions). This will put some stress on the gimbal bearing to ensure it is essentially centered and not cocked to one side.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,581
Re: Drive install.... how tight is too tight?

Back at it again today. I cant really tell if the marks changed much, I did notice that with the engine at its highest point the tool got stuc easiser. Im gonna lower it back down some. Im using a digital caliper to gauge the distance between the mounts so that I raise it evenly.

Just have to realize that the distance between the mounts do not have to be equal on both sides if the stringers happen to be higher one side vs the other.
 

Knot Waiting

Senior Chief Petty Officer
Joined
Jun 23, 2006
Messages
761
Re: Drive install.... how tight is too tight?

By that, he means to put the alignment tool in place and then lift on the alignment tool, press down on it, pull it to the left and the right (all directions). This will put some stress on the gimbal bearing to ensure it is essentially centered and not cocked to one side.

Yessir. Once the the tool was in the coupler (as much of it as I could) I tapped around the tool to make sure the bearing was in line.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,581
Re: Drive install.... how tight is too tight?

did you set the gimble bearing?

If he is getting the alignment tool into the coupler at all(He is) the gimbal bearing is already set in the proper angle. No need to worry about this anymore.
 

Knot Waiting

Senior Chief Petty Officer
Joined
Jun 23, 2006
Messages
761
Re: Drive install.... how tight is too tight?

Just have to realize that the distance between the mounts do not have to be equal on both sides if the stringers happen to be higher one side vs the other.

Thats an interesting point that I hadnt thought of Bruce. [throws caliper across shop].
The only thing that seems consistant here is that no matter where the engine (in the places Ive checked it) is that the tool seems to bump up very slightly upon entry and only goes in about an inch. The spline marks seem a little heavier on the bottom but that may just be because gravity nautrally pulls the tool down a little when removing it.

Maybe I need to measure the stringer height.... Maybe I just need to pay someone, lol. I just feel driven to figure this out because otherwise its like admitting defeat.
 

system-f

Senior Chief Petty Officer
Joined
Dec 3, 2008
Messages
667
Re: Drive install.... how tight is too tight?

I do not think you are here yet, but one thing to remember:

I had an alignment bar cut out of stainless to Don's Merc specs and once i got the engine aligned the bar would make a clunck and stop. It took us about 30mins to figure it out, but the end was bottoming out on the outside of the splines. We thought it would hit the gimbal first, but it didn't. Instead my tool bottoms on the coupler splines and it only looked like it was going in 2-3"s. The grease marks on the step right after the portion that entered the splines let us know this.
 

frank246

Petty Officer 1st Class
Joined
Jul 18, 2009
Messages
293
Re: Drive install.... how tight is too tight?

Have you checked the rear engine mountings, broken/ missing lock washer(s) or bad/ missing fiber washer can cause the engines back to sit off center (to low).
Then adjusting the front of the engine will never get the coupler properly in line with the bearing.
 

Attachments

  • Mercrearmounts.jpg
    Mercrearmounts.jpg
    10.9 KB · Views: 0

Knot Waiting

Senior Chief Petty Officer
Joined
Jun 23, 2006
Messages
761
Re: Drive install.... how tight is too tight?

Mine clunks and stops..... but only at 1". From what I can see the front mounts look ok, its hard to tell though because they are in an awkward spot. Im thinking this has gotten beyond me and I may just (regrettably) pay someone to do it.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,581
Re: Drive install.... how tight is too tight?

If you do have someone do it, just bring them the boat without the drive on and have them leave it off so that you can double check their work.
 

Knot Waiting

Senior Chief Petty Officer
Joined
Jun 23, 2006
Messages
761
Re: Drive install.... how tight is too tight?

If you do have someone do it, just bring them the boat without the drive on and have them leave it off so that you can double check their work.

Exactly what I was thinkin. Im probably gonna bring my alignment tool along too so I can make sure nothing is wrong with it. Thanks agian for everyones help.
 

stonyloam

Vice Admiral
Joined
Mar 13, 2009
Messages
5,827
Re: Drive install.... how tight is too tight?

If he is getting the alignment tool into the coupler at all(He is) the gimbal bearing is already set in the proper angle. No need to worry about this anymore.

That is not exactly correct, at least not with my tool. Just went through the exact same thing last week. Installed new gimbal bearing in my nephew's boat.
The first and second shaft passed easily through the bearing, and the smaller shaft went about 1 inch into the coupler, then "clunk" the shoulder of the largest shaft contacted the bearing. The bearing was cocked ever so slightly and as soon as we straightened it out, the tool went in just fine.
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Drive install.... how tight is too tight?

Have you actually taken a flash light and looked inside the coupler? You may not have any splines left, except for the last 1". Wouldn't be the first one I seen like that.
The splines should come all the way out to the edge of your coupler.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,581
Re: Drive install.... how tight is too tight?

, then "clunk" the shoulder of the largest shaft contacted the bearing. The bearing was cocked ever so slightly and as soon as we straightened it out, the tool went in just fine.
That sure seems odd. On my tool, the shaft is at the diameter of the gimbal bearing before the end of the tool even reaches the coupler. The only way mine would "hang up" is if the tool had roughness on it.
 

stonyloam

Vice Admiral
Joined
Mar 13, 2009
Messages
5,827
Re: Drive install.... how tight is too tight?

That sure seems odd. On my tool, the shaft is at the diameter of the gimbal bearing before the end of the tool even reaches the coupler. The only way mine would "hang up" is if the tool had roughness on it.

You are absolutely correct, I double checked mine today and the larger diameter shaft does enter the bearing before the smaller one contacts the coupler. Thanks for the correction.
 

Knot Waiting

Senior Chief Petty Officer
Joined
Jun 23, 2006
Messages
761
Re: Drive install.... how tight is too tight?

Have you actually taken a flash light and looked inside the coupler? You may not have any splines left, except for the last 1". Wouldn't be the first one I seen like that.
The splines should come all the way out to the edge of your coupler.

From what I could see with my shop light the splines were right up to the end of the coupler, tapered off and everything. The splines on the driveshaft are squared off and look like new. I even reached inside the coupler from behind the engine to feel for any abmnrmalities and everything felt fine. Only noticeable texture in the coupler (aside from alot of grease) was a small raised ridge less than a mm high around the entire inside circumfrence of the coupler... about one inch in.
 

Howard Sterndrive

Rear Admiral
Joined
Nov 5, 2008
Messages
4,603
Re: Drive install.... how tight is too tight?

I'm at the exact same place. I'm perfectly aligned and my bar won't go past 1 inch or so. The drive won't slide in either.

I'm pulling the engine.

I'm to the point where I'm questioning the new coupler I bought. I never thought to try it on the splines of my drive before putting the engine back in.

I'm going to put the old coupler back on.
 
Top