Engine alignment off sideways, what's causing this?
 

All theories are welcome, high and low! 🙂

Put a 1" (25mm) tube into the coupler after engine and transom assembly switch to make a rough alignment before doing the final one with correct alignment tool. This is what I'm looking at, the engine is off sideways.
I'm going to try to push it sideways in the front but the rear mounts are in place with bolts through (not tightened up yet).
Boat has 300 hrs (sea ray 2001), never been sunk, transom sounds firm when knocking, boat has a history of vibrations so just installed a new transom assembly and a "new" used engine because vibrations damaged both. Never rebuilt transom.

Has anyone seen this much misalignment sideways before? What caused it?

https://cimg1.ibsrv.net/gimg/www.off...eb97c659b2.jpg

This might sound stupid but have you turned the engine over by hand to see if that tube moves side to side?

Actually haven't yet, I'll do that thanks. The old engine and transom had similar misalignment but ripped those out before trying to fix it. Was surprised to see the same issue with new engine and transom assembly.

the two engine mounts on each side that mounts to the stringers have slots in them for adjusting the twist. Loosen them up and move it to where you need it then tighten back down. I have over 35 years mercruiser tech. Thats more than likely it

I don't know what you're trying to ask here. Your rear motor mounts aren't tight and you need a front motor mount. Just by tightening bolts up, it's going to shift to position of the alignment.

I have front motor mounts, had nothing to do with this really (edited the post). Well you have a point, I might have jumped the gun before ruling everything out, just that the old setup had the same shift to the side and now the new one has the same. I'll know in a couple of hours if there's room for 3/16" sideways play on the rear mounts by just tightening the bolts. But I find it unlikely.

I'll go and try right now, thanks for the tip. I'll report back in a couple of hours.

Well, if the alignment was off and they managed to cram the drive on, that could possibly explain the vibration....

Managed to move the engine quite a bit to the side on the front mounts and the side alignment got a bit better. But its still off center. Going to try to remove the rear mount bolts entirely just to see if I can get it centered at all, with all the mounts out of the equation.

I strongly believe this has been the case. Previous owner replaced the coupler two times, and the orifice on the old transom assembly, where the gimbal bearing sits, had been worn out to the point that a new bearing could be installed and removed by hand.

Shoulda been investigated the first time a coupler went bad. Misalignment is usually why they fail.

Did you find out if the angle changes by rotating the crank 90* ?

I didn't unfortunately, but good to have ruled it out.

Theres a special alignment disc you can purchase (i'll try to scare up a part number). It fits into the transom assembly and then the alignment tool goes thru that. The bell housing has to be straight left and right and 90 to the crank or the shaft wont go thru the bearing and then into the coupler.

Kinda proves the gimbal bearing isnt all wacked out either since the engine looks low in front and to the right.
guess it also shows if your rear mounts have sagged.

post up the engine drive and transom serial numbers so these guys can help you figure out if you have the correct stack on the rear mounts or not as well.

also if that's pvc you'd be the first guy in the world to have a straight piece, use the alignment tool ?

No worries, I have the tool. This pipe was just to give it a rough alignment when its way off. The tool goes in and out now after some adjustment, but its still off to port side and that's not good. Up and down is good.
I've got the old motor mounts with new double wound spring washers and fibre washers. That doesn't fix the side alignment unfortunately.

If your chewin up couplers and having a problem aligning I would take a hard look at your transoms condition.

are the nuts that secure the transom torqued the same amount,sounds like 1 side of the transom is squeezing in more than the other.remember,1/8" at the transom,turns into an an 1" farther out.

Yes it's torqued to spec. From what I could see by just measuring to two top bolts, the port side protruded 1 mm shorter from the nut. That adds up to the misalignment. Also turned the engine as far as I could in the front to the port and it got a little better.
The alignment tool now went in absolutely perfectly, so decided to bolt everything down, put the drive on and going to sea trial it to see what happens.

An update, it still vibrates on sea trial. Lighter but faster vibrations going forward, slower and more prominent going backwards and turning. The harder the turn going backwards, the more prominent the vibrations gets.
The only thing I haven't replaced is the outdrive so that's probably next on the list. I'd prefer to be able to try with another outdrive but I just presume no one is going to lend it to me with the risk of it taking some damage if it's an alignment issue.

I've had the same problem on an older MCM Alpha 1, could never get it to aligned laterally. I finally gave up after fighting it for a few seasons, pulled the engine, the inner transom plate and it became immediately evident that I had a soft (yes water) transom on one side and not the other. I rebuilt the transom and it was amazing how nice the shaft engages the coupler!
That may explain your variation in exposed threads on your fastener set. Good luck, hope I helped a little!

U joints?
When you installed the transom assembly, did you follow the tightening sequence and number of passes until the 25 foot pounds was achieved ?

Do you have matching flywheel cover and inner transom plate ? Some rear mounts used the fiberous washer and spring, the newer ones i don't think use them. An old rear flywheel cover won't align with a newer inner transom assembly and vice-versa and with wrong/incorrect stack between the rear mounts.

There are pictures and mercury service bulletins connection with the rear mounts on here and all over the internet.

Thanks, I've read that a soft transom might cause this type of behavior, but I I'd like to rule exactly every other thing out before having to face that fact.

Yeah I'm hoping it'll be an outdrive issue. Yes, I've done everything by the merc instruction with torque-procedures, paying extra attention to the old vs new washer-situation so those are correct. I'm pretty meticulous 🙂.
That would only affect the height, not the lateral adjustment though.

https://cimg8.ibsrv.net/gimg/www.off...17e37010a7.jpg

in my opinion, this is the alignment tool you need, (in conjuction with the shaft), It fits into the transom assembly and on the alignment shaft tool. It wont sit flush unless the engine crankshaft, drive coupler, gimbal bearing and outdrive bellhousing are all in alignment.

https://cimg1.ibsrv.net/gimg/www.off...833c02caa2.jpg

Here is the part number

https://cimg9.ibsrv.net/gimg/www.off...298e3832df.jpg

It diagnoses ; improper gimbal ring height. improper/ sunken rear engine mounts. Mis-aligned gimbal bearing, bad engine coupler via spinning 12-3-6 & 9 and other engine alignment issues, etc.

And, IF, you have the bearing hangar from a alpha/bravo driveline it can also show an out of square/flush/parallel inner transom plate to transom assembly.

https://cimg7.ibsrv.net/gimg/www.off...704b100a22.jpg

It is also absolutely neccessary if you ever decide to install an engine other than the way mother mercury would have you do it all the while using some but not all aftermarket parts in such a way as to pull engine install and alignment directly out of your ass and have it work

https://cimg6.ibsrv.net/gimg/www.off...4e5816dc8c.jpg

https://cimg4.ibsrv.net/gimg/www.off...282e82a565.jpg

I have offshore mounts for engine (front) and trans (rear) tubular hoop style.

Coupled to ASD6s.
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​With zero alignment adjustment, what is the best process to ensure parallel alignment?