Engine Alignment, weird issue

[justthisguyyaknow]

Older starcraft boat with a 120hp Mercruiser, and a pre-alpha outdrive. I removed the engine to replace the coupler which was trashed by shifting into gear at a very high RPM (another post/another story). The engine is re-installed, and the hardware on the rear mounts is the double-wound springs and fiber washers, just like it should be.

I'm having a devil of a time aligning the engine for the outdrive, though. I finally removed the front mount, and switched to using a chain hoist so I can easily move the front of the engine up and down, just as a "proof of concept", planning to record the inclination of the valve cover from my inclinometer when I find the right spot.

At the sweet spot, I can get the alignment bar PART WAY in to the coupler (perhaps 1-1.5 inches), and no further. It's not a hard stop when pushing in, it feels like it binds up. The weird thing is that when I grease the bar, I am seeing even spline marks in the grease clear around the bar (the portion that makes it in), suggesting a good alignment. And yet, as I say, the bar won't go in all of the way (and it needs a good yank to get it back out), suggesting a bad alignment.

The spline marks show that I'm at the right spot, but the tool not moving in and out relatively freely shows that I am not. The tool IS going through the gimble bearing fine.

What could I be missing here?

 

[achris]

justthisguyyaknow Welcome to iboats. (Do you know my friend Ford Perfect?)

Could be just a new coupler being tight... Did you move the gimbal bearing around?

(You don't have a ''pre-Alpha"drive, nobody does. You have an 'MC-1'...)

Chris....

 

[justthisguyyaknow]

I do know Ford, and Arthur, oh yes.

I should clarify that the "new" coupler is actually a used one. I did test the used one by sliding in onto the removed outdrive, though I didn't ever try inserting the alignment tool into the used coupler before mating it to the engine (in retrospect, I believe I should have).

And yeah, I don't have a pre-alpha, I know. I'm just kinda going with the flow on that terminology, but I know that's like having a coin stamped "120BC" lol.

 

[alldodge]

clarify that the "new" coupler is actually a used one.

If the used coupler came from a boat in which the drive was a bit out of alignment and then sat in one position for a long period of time, this could have put a set in the rubber. It might come out in time.

Assuming when the alignment bar is first inserted just a bit, the bar is smacked around up/down/left/right a few times with your hands to center the gimbal bearing, before further inserting

removed the front mount

Raising by a hoist is best method to start, but once lifted and close to spot, the mount should be adjusted to hold motor. Then continue with mount adjustment. The hoist can put the motor in a slight twist.

 

[justthisguyyaknow]

Back on the mount, same adjustment and same problem. The tool goes in, only goes so far, then binds up. The grease marks look consistent all around the bar. I've measured the bar, and it is true.

I've been desperately trying to find a 1" outer diameter long bar or pipe to try to be sure that, when inserted, it looks centered in the gimble bearing. Nothing at my local hardware fits the bill. Obviously, if the rear of the engine is sitting too low (or high, left, right), the whole operation is doomed to failure. It should be, but the parts are around half a century old, so...

 

[wellcraft-classic210]

If your looking for 1 inch metal stock -- You may want to ask a steel supplier, machine shop or possibly a metal scrap yard // or even order on line Mcmaster-carr etc

 

[justthisguyyaknow]

I found a 1.005" bar (from an old TV tray, but pretty straight). The front of my engine needs to move starboard slightly (the board to which the front mount attaches has a few mm of play left to right, suggesting it has shrunk over the years). Next step is to try to get the engine centered in the horizontal axis. Argh.

 

[achris]

Remove the coach screws from the front mount, lift it very slightly (so there is no weight on the mount) and let the engine find its own position (right to left).. then drill new coach screws holes...

Chris...

 

[Rick Stephens]

Translation:

------------- Coach Screw -----------------------------------------Lag Bolt --------

-----------------

 

[wellcraft-classic210]

Also -- you may want to check for runout by spinning the crank and looking every 90 degress or so // then split the difference if their is any runout. ( 1.00 shaft wobble )

 

[nola mike]

Translation:

------------- Coach Screw -----------------------------------------Lag Bolt --------

-----------------

Ha, thanks for that!

 

[achris]

Yes, and the pictures refer to 'lag bolts' being up the right way and 'coach screws' being up side down (as in Australia)... :facepalm:
Chris...

 

[wellcraft-classic210]

HMMM funny stuff

Now I'm wondering what are they called when trey are horizontal ?

 

[achris]

HMMM funny stuff

Now I'm wondering what are they called when trey are horizontal ?

Still called coach screws where I live...

Chris..

 

[rickasbury]

I found that an aluminum broom handle was close enough to 1" to get me close. It does not make sense to me, having been through this that if the grease marks are right then it should go in- if it has a bad "set" to it or otherwise binding, it will show on the grease...the grease shows it all right?

 

[wellcraft-classic210]

Regarding the alignment bar not going in// Are you able to verify the diameter of your alignment with a vernier caliper or similar ? pay attention to diameter, surface condition and runout ( as in not oblong ) // Is the Gimbal bearing which pivots is aligned and sending the bar in the correct direction.

 

[justthisguyyaknow]

The grease does, I'm not positive on the alignment tool being right (eBay), but I got it centered and the outdrive installed easily. Somewhere I have a good alignment bar, I need to find that.The left/right alignment was easily accomplished by moving the wood to which the front mount is attached (you'd have to see the boat).

I then put my cell phone camera back to view the coupler when the engine was running, and it had no wobble, turned easily and quietly. With the plugs out, I can actually easily turn the engine all the way through to the prop. I also replaced the outdrive oil for good measure.

In other news, my broken outdrive was NOT broken after all. It was making a terrible noise when I turned it by hand while off of the boat, which I swear sounded like gears grinding. Turns out the noise of a dry impeller is very noticeable even just turning it a single revolution by hand. When I hooked up the muffs, the noise disappeared. Still wouldn't hurt to have a spare outdrive, so I'll keep my eyes open for one.

Other problems along the way:
* I did manage to fry an ignition coil (though I think that's coincidence on the timing, and was easy to replace)
* I also somehow managed to cross-thread one of the bolts for the tilt/trim rams (which I'll just have it re-threaded at the hardware).

Thanks to iBoats, eBay, and O'Reilly, I'm now back in business, all is working.