View Full Version : Engine alignment

Dr. David Fleming
11-01-2010, 11:00 AM
Just bought the merc alignment bar - have had the drive off a couple of times. Any comments on how difficult this is to use? Service manual adjustment procedure seems to be trial and error method of raising and lowering front motor mounts. Reading grease tracks with discussion about leaning on the bar to see if it goes in easy? What about side to side alignment? Are the rear motor mount bolts on the transom involved in this alignment?

Anyone checking engine drive alignment on a regular basis? Aside from wearing out the engine coupler and gimbal bearing is there any performance gained or lost in drive alignment?

11-01-2010, 11:02 AM

Dr. David Fleming
11-01-2010, 12:51 PM
MOP thanks for your post but I can't access it.

11-01-2010, 01:19 PM
i check every time i have a drive off,you have to do a bunch of them to get the correct feel and know which way to adjust the engine by the Greece tracks left on the tool from the splines..side to side is adjusted on the bottom of the motor mounts the bolt through the stringer plate,the motor mount bolt holes are notched to slide side to side but you have to loosen all bolts to do so..no adjustment on the rear,their is just some springs,leather washers and some rubber bushings and a bolt and spacer that goes through it..you will rarely have to move the engines side to side adjustment. if the tool dont go in easy you may have to take plastic dead blow hammer and lightly smack the end of the tool @ 12=3=6=9 o'clock position the alguien the gimbal bearing...once it goes in it should be nice and smooth with minimal spline marks on the Greece on the last 3'' of the tool.

11-01-2010, 07:26 PM
MOP thanks for your post but I can't access it.

Odd the link works fine from this post, but go to the tech articles section under "Engine Reinstall" it will get you straight.


Dr. David Fleming
11-01-2010, 09:16 PM
Ok guys thanks for the heads up on starting this - one more thing - aside from wearing out the coupler with bad alignment - is there any performance lost with out of line engine?

11-02-2010, 10:28 AM
The worst I have seen is the bearing spinning in the shield, the coupling can in many cases leave you right where it burned out. Being out of line can cause side loading on the U joint, most of us have heard the rumble when the steering id hard over. It is one of those do it or else things, it will get you one way or another.

Dr. David Fleming
11-04-2010, 04:09 PM
Thanks for the help on engine alignment -

I am getting the bar into the drive through the gimble with a slight tap 9-12-3-and 6 - grease on the splines. Have located the motor mounts four screws in the hull - in slots for right and left. Two nuts on motor mount pin - each side - that hold the engine with a sheet metal lock washer for locking them. Now I loosen the top jamb nut and raise or lower the engine with the lower nut using a large open end wrench. When my grease pattern is even all around the alignment bar and it goes in and out with two fingers I tighten up the jamb nuts and four mounting bolts and verify the alignment has not changed.

Then I grease the u-joints and coupler with Merc special grease. Then reload my drive clipping the shift cable, attaching the speedo tube bayonet, and torquing all six attachment bolts.

What have I missed here - do I torque the engine mounts to any particular tightness? How tight the ones into the fiberglass? did I miss anything in the lube supply to the drive?

Any particular kind of driving or storage that causes the alignment to shift out of position? Are some boats more likely to need this adjusted all the time?

thanks again