Coupler/Gimbal Bearing alignment help

radscoot

Member
Nov 8, 2016
95
Georgian Bay, Canada
Boat Info
260 Sundancer, 2006,
Engines
5.7 Merc/Bravo 111
Hi
I have an 2006 260DA 5.7MPI Bravo 3 with 266hrs on it.
Last season our first, we put 90 hrs on it with no issues.
Drive came off no problem in the fall and I put it in my garage to service and paint touch up.
I am getting it ready for the new season and I just replaced the Impeller, Gimbal Bearing, Bellows, shift cable etc.
I am now trying to get the alignment setup with the new gimbal bearing. Alignment is fine in one direction ( 2 finger push/pull) but when I turn engine 180’ its completely out.
Along with the Merc alignment tool I am also using a 1 inch steel rod to insert into the coupler to assist in verifying its centered with the gimbal bearing.
In the Aligned position the rod is perfectly centered with the gimbal but when the engine is rotated 180’ it will not go into the coupler its off so much.
Its as if there is a huge wobble in the coupler.
Yes I have been hitting the alignment tool at 90’ points to set Gimbal at each adjustment.
Has anyone run into this before?
Is it possible that this is an early sign that the coupler is failing and I just happened to catch it before it tore apart?
Thanks
Randy
 
Sure sounds like it...What if you split the difference with the adjustment ? May buy you some time.
 
There’s no way that’s OK.

I might pull the coil wire off and have someone crank the engine while looking through the bearing with a flashlight just to see what’s going on.

If the splined hole in the coupler is gyrating, you’ve got trouble.
 
There’s no way that’s OK.

I might pull the coil wire off and have someone crank the engine while looking through the bearing with a flashlight just to see what’s going on.

If the splined hole in the coupler is gyrating, you’ve got trouble.
I did and that’s exactly what’s happening.
What does not make sense is I had no issue pulling drive off and there was no indication of a problem with the Coupler last summer.
I am thinking with the drive on it was holding the Coupler in place. With the drive off the past 6 months the coupling sagged to one side that is close to failing.
I did a search on this Forum and with Google and I could not find any discussions with a similar situation. Most discussions are the couplers fail and leave you stranded.
I was hoping someone would chime and have a simple fix. All indications are I’m into pulling the motor and changing out the Coupler.
 
OK, so the coupler was in that aligned spot when you pulled the drive maybe.

I don’t see it sagging over time though. It’s pretty stout and not really long or heavy enough to lose its shape due to gravity or leaving the drive off for extended periods would be a known no no by now.

As much of a drag as it is, I’d be hard pressed to put it back together with this concern looming.

Long shot chance that it’s fasteners are loose on the flywheel, but if you’re taking it apart to check that, you might as well replace it.

Good luck.
 
Actually the drive came off in the worst alignment position. I could not get it to align from that position so I turned over engine 180’ and it aligned no problem.
I went back to previous and it was out.
It’s all very odd. With the 1 inch rod inserted I can definitely feel movement of the spline within the rubber by pushing up and down or left and right.
I am assuming that a new Coupler would feel a lot stiffer or no movement at all.
 
In those instances where I’ve had trouble getting a drive off, it was more about the drive shaft being stuck in the gimbal bearing than the coupler itself, so I’ll reel that part of my comment back in.

Your situation is admittedly odd, but all signs point to a new coupler.

I’d be interested in seeing what you find though.
 
A runout measurement will lead you to the root cause.

Only 4 things it could be.
1. Bad coupler *
2. Loose coupler **
3. Loose flywheel **
4. Very unlikely (but possible), Bad/Bent crank


* = Far fetched, but if the boat sat for an extended period of time with the engine far out of alignment (possibly boat blocked wrong)
and sitting in a particular direction (full sun 8-8) it is possible that the coupler "has taken a set", and is now off center.

** = In both of these cases, if either is loose they can move around and although bolt to hole clearance is usually minimal, if they
have been loose for long enough the holes could be elongated allowing the coupler or flywheel to shift.
 
If the engine was ever run with the leg fully raised, it may be possible the plate the coupler is mounted to has developed some deflection. Sound like it is time for a new one. I would be replacing the U joint at the same time.
 
Thanks all for the replys. All good info to research.
I did find this statement in the Manual which is info that is widely shared, you must do an alignment check at multible degrees of rotation. Good thing I was following this.
"Engine alignment incorrect or engine coupler crooked.
Adjust alignment. Ensure that alignment tool moves in and out of coupler freely. After proper alignment has been obtained, check for a crooked coupler by rotating engine coupler 1/2 turn and rechecking alignment. If proper alignment is no longer observed, coupler is crooked and must be replaced
."

I have also found a few discussions on other sites where they have come across defective couplers with the same issue I am having.
My dealer also informed me that a new stock coupler is on back order. Really makes you wonder how many of these things are failing. Apparently there is also an stronger coupler with a longer support for drive shaft. Its supposed to be for boats that do a lot of trolling which puts a lot of extra wear on couplers. I did a lot of no wake running last summer especially when we did a bunch of Locks in the Trent Severn waterway. So I may inquire about getting the stronger Coupler.
I will let you know what I find in the end. Its been frustrating so far trying to figure this out.
I imagine it would have been more so if it had failed when we were out somewhere far from home.
Cheers
Randy
 
You should have this coupler.

85416__86161.1500927618.jpg

It has a rubber hub. It will wobble some when the shaft is not inserted. I encountered the same situation when I replaced one a few years ago. The new one wobbled. I used a rod the same diameter as the shaft to align. Never had any issues.
 
Craig
Thanks
Hey in your last post you mentioned the Coupler wobbled a bit and you could align with rod.
I can do the same with mine but it does not stay in position at center. I was wondering how stiff is a New Coupler?

Randy
 
New coupler was stiff but not rigid. I fired my engine up outside the boat before I put it back in. Wobbled like crazy. Thought it was bad. But the shaft will center it. I set my alignment and I had no vibration at all.
 

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