Coupler Alignment on Mercruiser, Alpha 1

[Mik]

I had the coupler go bad on our 86 SeaRay Mercruiser (Alpha 1).

I pulled the motor and changed the coupler, no problem. I've pulled the Ujoint from the shaft and using the shaft for alignment (yes, the shaft fits correctly in the coupler).

I can get the shaft to go into the coupler, but it's tight. Grease on the shaft shows that it's high and to the right. I have a dowel that I'm also using as an alignment tool.

When I peer through the bearing to the coupler, it also appears that it's too high and to the right a little (1/16th inch, perhaps a bit more). The bolts on the back of the motor to the drive housing has no side to side give.

Because the coupler is too high, I removed the "double" wound lock washers that were under the rear motor mount (I could see light between the fiber washers and the bottom of the rear mount with a light and mirror) so I changed the "double" wound lock washers with a single wound (standard) lockwasher. This appears to help the height problem somewhat, but it almost seems that it needs to come down more and still needs to move the motor to the left.

I've searched the archives and there was one comment that suggested putting the alignment tool in the bearing, that there was some adjustment there, but it seems to be very rigidly mounted (even the drawings in my manual show this).

Is there something that I'm missing here? Could it have been out of alignment from the factory?

Incidentally, I pulled the plugs and turned the motor over to make sure that the coupler isn't misaligned (turns over smooth), it's OK.

Mik

[Mik]

Incidentally, this is a 140 horse 4 cylinder GM motor. The coupler is the Round type that bolts to the flywheel bolts, not the triangular type.

Mik

[Don S]

You need an alighment bar, not dowels, and not old splined shafts. The old shafts may work to verify the alignment is still ok, but it won't work when putting in new couplers, and possibly needing alignment because the engine was taken out, or parts missing on rear mounts, or new mounts installed or whatever.
When you are checking a coupler to see if it's misaligned, the engine will turn over easily, but the rubber will be flexing and you won't feel it. But, if you were using the alignment bar correctly and checked at 0 and 180 degrees, you would find you wouldn't be able to put the bar in after you turned the engine.
You need the proper tools if you want to do the job properly.

[Bt Doctur]

Like Don says, you need the proper tools.
you dont mention replacing the rear mounts that normally cause a failure.
front mount may be bad from a bad bushing or rotted mount and the front of the eng. dipped down a bit.

[cincinnati sundancer]

i think those " double lock washers" are actually little springs that give some lift for vibration reduction and the rear bolts don't get tightened all the way, they need about 1/16 of an inch space. thats why the nuts are locked in underneath. good luck

[Don S]

i think those " double lock washers" are actually little springs that give some lift for vibration reduction and the rear bolts don't get tightened all the way, they need about 1/16 of an inch space. thats why the nuts are locked in underneath

I sure hope no one reads that garbage and thinks that's how it's really supposed to go together.

[Mik]

I found the problem.

It was the front mount wooden rail (covered in fiberglass). The wood rotted from the bottom. I need to replace it.

Mik

[Bond-o]

I removed the "double" wound lock washers that were under the rear motor mount

You'd better put he Rear Mounts back together,... The way they Belong......

All adjustments are done to the Front Mounts,.......

[jmatteo1]

You may want to check some things that can only be replaced with the engine out. On mine, the exhaust shutters were bad, so I took the opportunity to do them then instead of having to pull the engine again later.
Good luck!