Engine Alignment

[Knot Waiting]

I pulled my sterndrive last night to replace the impeller, Don & Bond-O suggested it may be a good idea, boy were they right! Despide only being one year old, sand and whatever else had shredded the blades and heat melted the plastic pick up tube. Good call guys

Anyway.. My question lies on another point Don had made. While the outdrive was off I decided to check my engine alignment. Seems it has shifted again. I can get the tool in about half way but it seems to hang up on the splined engine coupler that you can see just beyond the gimball bearing. Doesnt bind by much but I can tell that re-installing the drive would be a four letter word.

How do I go about aligning the drive? I have the tool but do not know how or what way I am suppose to move the engine? The tool should bottom out when all is said and done right? Thank you for your advice - Logan

Forgot to mention: 89' Alpha 1 Tpe R off a Merc 350 - Thanks

 

[HT32BSX115]

Re: Engine Alignment

Howdy,

You may have some other "stuff" going on there depending on how old the boat is.

You may have engine mounts that are "dropping" due to rotten wood underneath the fiberglass and/or you may need to replace the rear engine mounts. Boat engines just don't go out of alignment for no reason......The main reason for checking the alignment is to check why it's out of alignment.

Regards,

Rick

 

[Knot Waiting]

Re: Engine Alignment

Hmm, I'd certainly hope nothing was wrong with the stringers. The boat is an 89 but she's only got 250 hours on her and spent most of her days on the trailer not bobbing around a marina. Every thing in the bilge is clean an dry, no mold or discoloration in the resin and the mounts are still a golden color.

I did however have a shop align it last year and they said they had to use an overhead crane to lift and reset the engine? Dunno about their honesty. Maybe they never got it quite right or didnt set the mount studs?

Any ideas? or how do I go about re-setting this? Thanks guys.

 

[erikgreen]

Re: Engine Alignment

If they had to re-set the engine, did they shim the engine mounts?

That would lead me to believe the mounts sunk a bit... other than just looking at them have you considered taking a 1/8" drill bit and doing some test drills? You can plug the holes with marine-tex or epoxy afterward. If the wood that's in there comes out dry, you're good, but if you drill and get black wood or water, then rot is happening.

Erik

 

[Knot Waiting]

Re: Engine Alignment

I dont recall them saying anything about shimming the engine, not to say they didnt. I'll check the stringers tonight. God I hope there is no rot. Is is possible to say they just shifted or vibrated out of place? I mean the boat is in superb condition and has never sat with water in the blge, nor taken any on. How can I adjust my engine in the garage? Do I have to pick it up and shim it? If so what do I shim it with. Or is there an adjusting nut or bolt to fine tune it. It really doesnt seem that far off.

 

[Fishermark]

Re: Engine Alignment

I went over some details on aligning in your other post on water pump issues.

 

[Knot Waiting]

Re: Engine Alignment

Thanks Fishermark, I found the instructions you left. I thought that my post had become abandon so I started a new one. So this shouldnt be too difficult to make small adjustments on then? Good idea with the grease to mark it. Do you think my engine could have just shifted slightly after a hard season of running? I have seirous hesitations about drilling into my stringers given the overall excellent condition of the hull and bilge. Thanks

 

[HT32BSX115]

Re: Engine Alignment

I hate to be the one to say this but, this is VERY common in boats to have rot in the engine mount blocks. Once they get rotten enough they start to "drop" and the engine will not stay in alignment. If the alignment is not checked frequently (yearly) is usually surprises you when the coupler fails. Then, when you pull the engine you discover the rotten engine mounts. The alignment should really NEVER change much at all.

Test drilling the mounts is a good idea. when I replaced my 460 with the 454, I had to relocate the engine mounts. I drilled the original holes a little oversize with a bigger bit and filled them with MAS epoxy mixed with milled fiberglass and wood powder. when I drilled the new holes I was happy to discover real dry hard wood in the mounts. My Boat is over 20 years old too!


Good luck.

I dont recall them saying anything about shimming the engine, not to say they didnt. I'll check the stringers tonight. God I hope there is no rot. Is is possible to say they just shifted or vibrated out of place? I mean the boat is in superb condition and has never sat with water in the blge, nor taken any on. How can I adjust my engine in the garage? Do I have to pick it up and shim it? If so what do I shim it with. Or is there an adjusting nut or bolt to fine tune it. It really doesnt seem that far off.

 

[Knot Waiting]

Re: Engine Alignment

If thats the case then I suppose I'll set it this year and sell it next if its off again. I dont have the means available to pull the engine so unfortunately Im stuck with what I got. Unless anyone knows of an alternate repair.

 

[erikgreen]

Re: Engine Alignment

You can use a tree and a cheap hoist to pull it... I personally rented a cherry picker from a local rental place. It takes some muscle, but it isn't hard to figure out how to do it.

If you're going to fix the alignment and use it, I'd suggest scheduling a re-check sooner than end of the year, maybe after 20 or so hours of use.. if it becomes mis-aligned, the most likely thing to happen is that you'll trash the engine coupler, which will end your season quickly.

Erik

 

[HT32BSX115]

Re: Engine Alignment

If you're going to fix the alignment and use it, I'd suggest scheduling a re-check sooner than end of the year, maybe after 20 or so hours of use.. if it becomes mis-aligned, the most likely thing to happen is that you'll trash the engine coupler, which will end your season quickly.

Erik

Yes. and if that happens the only way to fix it then IS to pull the engine.


Sorry,

 

[Coors]

Re: Engine Alignment

When I got my '88 boat;
it had 1/2" shims under the front engine mounts (rotten)
After I rebuild the mounts and rear stringers, no shims needed.
Alignment now holds, and engine mount lags, after running rough water, don't stick up 2" from the mount anymore.
Epoxy lessons are in your future.

 

[Knot Waiting]

Re: Engine Alignment

...UPDATE:
(why is it that word by itself makes me picture the hoarse voiced guy from Unsolved Mysteries going over new developments on stories)

I checked the mounts tonight. All is well, the stringers are rock solid, no discoloration, cracks or hollow spots. The engine mounts sit firm in place atop the blocks. However both nuts for the engine mounts had vibrated nearly off. Probably were never tight to begin with.

Could this throw the alignment off. There is no bolt to turn to raise the engine, only a nut to loosen and jam shims under. My problem is that the alignment tool nearly goes in all the way, so the engine is close. How do I determine how big a shim I need or where it goes. The ole grease marker method was inconclusive. Can I put force on the tool to pull the engine in or is that not a good idea? Any help is good, if I cant get this I gotta take it in and I really cant afford that. Thanks

 

[HT32BSX115]

Re: Engine Alignment

Glad to hear it's all tight!


No.

Don't force it. You cannot use the alignment bar to move the engine around. You need to either move the engine up or down equally using the front (underneath) nuts to run it up and down. It doesn't take much to get it where you want it. Once it's in the right place tighten the top nuts. If the top ones were loose then the bottom ones might have moved a little too as the engine moved around . I'm surprised you didn't toast the coupler. It must have not been that way for very long. If you cannot get the alignment right you may have a problem with the rear mounts. (possible but unlikely though)

If you're close, it'll just take a little more "twiddling" to get it right. make sure you put a good amount of spline grease on the shaft when it goes back in...

Glad to hear that the mount-wood is firm and dry!

 

[Fishermark]

Re: Engine Alignment

...There is no bolt to turn to raise the engine, only a nut to loosen and jam shims under.

There is an upper and lower nut as Rick mentions - no shims involved. It should look something like this:

You turn the bottom nut up or down to the correct adjustment height, then lock it in place with the upper. You might find it easier to take some of the weight off the engine with a hoist in order to turn the adjusting nuts.