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Motor Alignment?


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A bit of a PITA, but it's good practice. 

Here is a rough idea of what you are in for:

You will need to uncouple the shaft from the transmission.  Remove all 4 bolts.  Using a 0.003 feeler gauge, slip it around the mouth of the shaft coupler and the transmission coupler to see where the engine is out of line.  You need to be it to within 0.003' gap all the way around.   From here, you'll be able to tell which way you need to move it (left to right, top to bottom).  If it's simply moving it top to bottom, you can adjust the bolts by increasing/decreasing them along the mounts.  Check the alignment with the feeler gauge again.  You'll find yourself doing this a lot.  If the issue is left to right, you'll need to loosen up the engine mounts along the slider bar.  Loosen these right up, so that they are almost dangling off.  I had just back them off a bit and could barely get any movement out of my block.  The movements are slight, so don't expect to be moving inches each way.  Use a long metal pole wrapped in a blanket try to pry it between the bottom of the hull and the engine and begin moving it left or right.  Check alignment again.  Once you get it to the 0.003' tolerance, tighten up your motor mounts, check the coupler alignment again, then if all is good,  bolt the shaft coupler back to the transmission coupler.   Anything within the 0.003' gap excellent. 

This video shows the steps you need to follow.  It's the same principle for an Indmar V-Drive.

https://www.youtube.com/watch?v=MkzemrcgZ48

Edited by saxton15
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An indmar certified mechanic and Supra dealer himself said that is for 20 hour services only!!!!!

he is a minimalist and im not saying an Indmar manual doesn’t say that

he said it’s a major waste of time and money and not necessary 

I finally do my own fluid and pump maintenance and I asked him to do a shaft alignment this January as per OP’s on this site

he basically said if your doing that something major has gone wrong and your fixing something 

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I agree with Granddaddy that it can seriously mess things up if not done right.  But it's not rocket science.  Also, if you notice vibrations in your driveline, alignment is usually a good source of the issue.  I might be wrong (feel free to correct me anyone), but once you get it all lined up, it shouldn't get out of line unless you take a hit or some sorts or have a failure in some other regard. 

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The easiest way to know if it's properly aligned is to get under it and try to spin the shaft/prop by hand.  If it rotates fairly easily, then there is nothing binding, and it is in alignment.  If it's hard to turn, then something is going to wear improperly.  This is, of course, assuming you are checking it as a routine maintenance and like @saxton15 said, not after an impact or other failure.

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I'll be honest, mine is all lined up, and the prop is still fairly difficult to turn by hand.  I do have a traditional packing on it, but I would said I need to use a good amount of one hand force to get it to rotate. 

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11 minutes ago, saxton15 said:

I'll be honest, mine is all lined up, and the prop is still fairly difficult to turn by hand.  I do have a traditional packing on it, but I would said I need to use a good amount of one hand force to get it to rotate. 

Especially if the cutlass bearings are dry.

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I wouldn't count on just the prop spinning to decide whether or not your alignment is good.

It's really not that hard to align a motor. I actually found a REALLY good instruction set in the PCM owner's manual that explains exactly how to adjust, based on where the alignment is off.

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  • 7 months later...

A friend of mine has a Moomba and he got a quote from a dealer to pull his motor and reinstall it again. He was told they would pull the motor together with the transmission. I think it was around $1500-$1700 what they wanted to charge, that is specifically for that part of the work (pulling/reinstalling motor). He is deciding if he wants to pay or do it himself. If aligning is just that, it looks time consuming but not hard. Other than that, I imagine that pulling the motor is just a matter of keeping track of what you remove and reinstall the same way.

Edited by Javi
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7 hours ago, Javi said:

A friend of mine has a Moomba and he got a quote from a dealer to pull his motor and reinstall it again. He was told they would pull the motor together with the transmission. I think it was around $1500-$1700 what they wanted to charge, that is specifically for that part of the work (pulling/reinstalling motor). He is deciding if he wants to pay or do it himself. If aligning is just that, it looks time consuming but not hard. Other than that, I imagine that pulling the motor is just a matter of keeping track of what you remove and reinstall the same way.

Alignment is not hard, like the others said.  I removed my strut to straighten it and did an alignment after I reinstalled it.  Of course, I put the strut back on in line with the shaft, so I only needed to move the front of the engine over about 0.030" or so.  I loosened the nuts until I had that much gap between the nut and the mount, then used a 2x4 to nudge the engine over.  It doesn't take long, but it does make you think about what needs to move and how much.  I found that the worst part is that the coupler flanges can rust slightly and create high spots that will make the feeler gauge lie to you.

Also, it is best to do your alignment with the boat floating in the water so the relative hull and engine locations are not distorted by trailer bunks.

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3 minutes ago, justgary said:

Alignment is not hard, like the others said.  I removed my strut to straighten it and did an alignment after I reinstalled it.  Of course, I put the strut back on in line with the shaft, so I only needed to move the front of the engine over about 0.030" or so.  I loosened the nuts until I had that much gap between the nut and the mount, then used a 2x4 to nudge the engine over.  It doesn't take long, but it does make you think about what needs to move and how much.  I found that the worst part is that the coupler flanges can rust slightly and create high spots that will make the feeler gauge lie to you.

Also, it is best to do your alignment with the boat floating in the water so the relative hull and engine locations are not distorted by trailer bunks.

Rust 😳

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27 minutes ago, Bozboat said:

Rust 😳

Salt water.  I do what I can (and in fact, I would compare my engine to any fresh water one, especially a 20 year old one), but that's one area I just can't convince myself to break apart just to clean it up.  I shoot it with spray lube a few times a year and call it good.  And I fixed the strut right after I bought the boat, so it was that other guy....

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I can tell you I have seen prop shafts snap due to improper alignment, once even in my own boat.  It is pretty scary (and expensive) to have that prop shaft slide out past the shaft seal and have water coming in.  If you aren't 100% sure you got it right, go find someone who can be. 

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On 5/3/2018 at 8:12 AM, granddaddy55 said:

An indmar certified mechanic and Supra dealer himself said that is for 20 hour services only!!!!!

he is a minimalist and im not saying an Indmar manual doesn’t say that

he said it’s a major waste of time and money and not necessary 

I finally do my own fluid and pump maintenance and I asked him to do a shaft alignment this January as per OP’s on this site

he basically said if your doing that something major has gone wrong and your fixing something 

If you have had the alignment done at 20 hours, never hit anything.....ever, and are sure that everything was tight from the factory and has never come lose or shifted in the least, then he may be right.  If he isn't, you'll get to replace your prop, prop shaft and possibly your rudder at a minimum.  But you will have likely also put stress on your v-drive/transmission and your cutlass bearing, which could be a fun surprise later in the life of the boat.  That also makes the assumption that the person who did it at 20 hours was a good mechanic and not summer help.  You don't have to have vibrations in the drive-line to be out of alignment.  Vibrations are more likely to show up as things don't rotate evenly, like a prop or shaft that has a wobble in it.  An alignment issue will feel completely normal, if the shaft and prop are true and straight.  And with the weight we put in these boats now, think of the stress we put on these drivetrains coming out of the hole.  I would put motor/shaft alignment as a close second to oil changes and winterizations on my list of important things to make sure are done right and stay that way. 

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On 5/3/2018 at 8:19 AM, saxton15 said:

I agree with Granddaddy that it can seriously mess things up if not done right.  But it's not rocket science.  Also, if you notice vibrations in your driveline, alignment is usually a good source of the issue.  I might be wrong (feel free to correct me anyone), but once you get it all lined up, it shouldn't get out of line unless you take a hit or some sorts or have a failure in some other regard. 

I believe you are less likely to feel vibrations from an alignment issue than you are a bend or ding in the shaft or prop/rudder.  With everything else being true, you won't feel the vibration, because things aren't producing a wobble or loping feel/motion.  You could feel some, but are way more likely to feel it because of a ding or bent shaft.

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@Fred4:  An engine alignment is a maintenance item, whether at a specific interval or after an incident.  Do you know if you need one, only really after you check it.  Signs that you might would include shaft bearing wear, perhaps some vibration, out of align setup can make a noise on throttle off and/or the shaft stops spinning faster than expected (less than 1 revolution).  A really well aligned setup with a good shaft bearing will free wheel due to 'neutral engine torque at idle' or prop spin force.  Spinning the shaft may or may not tell you, the type of shaft bushing you have (rubber or vesconite) makes a difference in the ease of shaft spin, and an out of alignment shaft can wear the vesconite ones so they spin free.  It is an easy process, simply removing the coupling and checking the gap and also checking to ensure it does slide on to the coupler without vertical or side movement (this step tends not to be noted on the alignment process).

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  • 1 year later...
On 5/3/2018 at 7:19 AM, JeffK said:

Absolutely correct. 

Definitely correct, had to find out the hard way. Don't be hasty with adjustments, take your time to be sure you've aligned the engine to coupler to 0.003" at a minimum. 

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Willing to bet that more of your engine mounts are not as tight as they should be. I just checked my alignment on my 18 LSV and almost all of them needed cinched up. Had dealer check them last winter due to a clunk in drive line, Don't know what hey tightened but clunk has been gone last 100 hrs. My alignment was only off .002"  Got her back in by adjusting the one mount I suspect they just tightened last year without rechecking alignment.

You need to be a contortionist with long wrenches to access the blind mount bolts in my LSV.

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