View Full Version : Alignment was easy

03-28-2004, 05:02 AM
By aligning the prop shaft with the engine/trans output shaft I have ended vibration that had been bothersome for the last season or so.

It was easy with a couple of socket wrenches and a feeler gauge, plus a hammer & screw driver to separate the flanges, and a mill file to clean-up the flange faces afterwards.

Was "out" by nearly 0.040, which is huge.

Dropped front of motor 2 1/2 turns on the mount jackscrews. Droped rear of motor/trans by 1 1/4 turns. Got better than 0.002. Expected to raise the unit, not lower it. Nevertheless, it worked great on the water yesterday, no more bad vibe. Did it on the trailer. Will double check it on the water next time we go out, had too much else going on when we tried it yesterday.

Next project is to replace the rubber lined cutlass bearing and realign once again. Intend to access it by pulling the prop and the prop strut off.

03-28-2004, 02:51 PM
Thanks for the post.....Have had mine supposedly checked by marina,but think i will
do it myself this spring ven though i'm having no vibration or other problems. Curious as to what yr your boat is? Also how often should the cutlass bearing be replaced?

03-28-2004, 02:58 PM
We have a 99 Outback with about 330 hours. This is our sixth season with it.

I've not replaced the cutlass bearing yet, but noticed some movement in the shaft when disconnected from the transmission, so I figured a new one would stiffen it. I don't have an answer for what is typical, but I wish I knew.

03-28-2004, 02:59 PM
We have a 99 Outback with about 330 hours. This is our sixth season with it.

I've not replaced the cutlass bearing yet, but noticed some movement in the shaft when disconnected from the transmission, so I figured a new one would stiffen it. I don't have an answer for what is typical, but I wish I knew.

03-28-2004, 07:52 PM
i have a 99 outback ls with the ballast tanks and a tower. Its carburated and i've been thinking of adding a holley throttle body fuel injection to it but it has been hard to get useful info out of these guys. my boat is greatand they all just want me to buy a new one with fuel injection. anyways mine has about 220 hrs on it and onlyhave had to replace the fan belt and blower as they were getting noisy.

03-29-2004, 12:03 AM
Yes, wish I had sprung for injection originally, but it was an impulse buy and there wasn't one on the lot!

I replace the fuel filter at least once per season. Several times, this has made a huge difference in preventing stalling. And it seemed to help a bit on hot restarts.

I also always run the highest octane petrol I can find from a modern gas station ( less chance of contamination ).

Not sure I would tackle a conversion, unless I was stripping an identical injected boat and directly replacing parts side-by-side with mine. Carb set-up does not seem that bothersome. Would be very wary that all parts were marine-rated. Not sure how they handle electric fuel pumps in terms of collision cut-off circuits, etc.

03-29-2004, 07:08 PM
When you did your alignment check, did you just hold the flanges together by hand when you checked them with the feeler guage?

03-29-2004, 07:33 PM
did you just hold the flanges together by hand when checking with the feeler guage?

03-30-2004, 04:55 PM
Catdog, when you did the alignment, did you just hold the flanges together with your hand when you checked with the feeler guage?

03-30-2004, 08:46 PM
Well, sort of.

I completely separated the flanges and cleaned-up the damaged faces due to the screwdriver used to separate them.

Then, I brought them together. There is a self-centering feature on them. I actually pulled the prop shaft hard enough to bump the flanges together.

Then I checked it with the feeler gauge all the way around. Gap was max towards the floor, no gap facing the sky. It looked good right to left.

Then I separated them, rotated the prop shaft 180 degrees, and bumped them / checked them again.

Then checked again and it seemed the same. So, I concluded that the prop shaft flange was square on the shaft.

Then, I commenced to adjusting the motor to remove the gap. In my case, the gap was maximum where it faced the floor, and the flanges were contacting each other facing the sky.

Don't know if this was the best course of action, but I got rid of the vibes.

03-31-2004, 12:37 PM
Catdog, Because we're dealing with feeler guages no thicker than a piece of paper (at most), I found that if I didn't hold the flanges togerther I could always insert a guage thicker that the recommended .003" guage. However, when I held the flanges together with my hand I could not. Since this was the first time I have checked my alignment I wanted to make sure I was doing it correctly. It seemed to me that trying to discern between .001" was pretty darn difficult because a little less pressure in holding the flanges together would account for that microscopic difference easily.

Was it pretty obvious that the flanges were out of alignment in your case?

Thanks for your input on this.

03-31-2004, 04:04 PM
I hope not to confuse the issue. You have to remember that the shaft is fixed at the prop end by the cutlass bearing (which may be worn). The flange end floats freely ( it only appears fixed by the stuffing box). You must establish that the shaft is truly centred in the stuffing box before checking the flange against the motor. I place a wood shim under the shaft. This also holds the shaft flange hard against the motor flange while you check it. Failure to do this could mean that the shaft is alligned with the motor but not with the boat. This will cause wear of the stuffing box, shaft and cutlass bearing.

03-31-2004, 07:15 PM
Each time I measured, I bumped the shafts together and held them by hand, if needed, so I couldn't get a guage between the flanges at the top, which is where mine interfered with each other.

Initially, with no adjustment, I had huge gap, low on the flanges.

I had vertical movement on the shaft, but little right/left. So, I kind of did what purplepower suggested, by eyeball centering in the flange nut. Rather than a block of wood, I guestimated that the prop shaft flange had to be lifted about two thirds of the vertical movement that was possible.

So, I lowered the back of the motor until the top of the flanges were about even.

Then, I lowered the front of the motor to reduce most of the gap.

Then, I went back and forth between front and back, tweaking each pair of bolts a little.

I guess, the more I write, the less confidence I'm feeling here!

04-01-2004, 01:20 PM
Your logic and methods sound fine to me. The point I was making is that you need to establish that the shaft is centred before comparing height the the motor flange. As you stated, there is a range of movement when it is not coupled to the motor. Gravity alone will force the shaft to drop out of centre.

I free off the packing gland during this operation. This makes it easier to check the shaft is centred. The motor mounts on these boats are very clever making this job a snap. Many inboards require lifting and shimming the motor which can take hours to get just right. The mounts on the Moomba can be adjusted in minutes.

04-02-2004, 04:55 PM
I concur Catdog. Sounds to me like you did alright. I had heard that you could bolt the flanges together but when I was doing the check, I realized that if I bolted them together before I checked I would be able to obliviate any gap that existed with less pressure. That's what prompted my question.

We're talking micromilimeters here and it really seemed much less precise and more subjective to me than that.

Glad the bad vibes are gone for you and I'm glad there are people I can bounce this stuff off of who know what I mean.

04-04-2004, 07:58 AM
No problem carsondoc. It helps us all to discuss this stuff. I'll bet our collective solutions are better than we can buy from the boat mechanics --- and a whole lot less expensive. I'm going to try to dissassemble this thing again to check it. I want to doublecheck that I used purplepower's thinking in this process. When I get it apart I'll snap some pictures, just for whoever else follows us.

06-23-2004, 10:27 PM
hi guys, just put in a shower for those chili mornings, and decided to check the shaft alignment. it was out about .020, open on the bottom side. I used your post and the alignment instructions. 3 turns on the port front foot and 3.25 turns on the starboard front foot gave me no gap at all. could not even fit .002 in. I did this on the trailer, i'm curious as to if it will be the same in the water. has anyone checked after trailer adjustment to water alignment? I will let you guys know in a few days when i go out again. Oh and the shower install was a snap.

06-28-2004, 09:58 PM
Checked the alignmenet on the water and it was the same as on the trailer. Oen thing i did notice, was that being on the trailer for a couple of weeks i had more windshield spread as has been reported in other posts. Once i was back on the water and on my lift cradle i'm back to what i've had for 5 yrs. Maybe something to do with the trailer?
Best boating

07-26-2004, 10:21 AM
Did you ever get a chance to post any follow-up pictures?

I am going to be working on my Kanga alignment today; however, I'm still weary of eyeballing the prop-side-shaft for center, and being able to determine gap with merely holding the flanges together.

Although I don't have the bad vibration you experienced, I have a *new* engine that runs fine without load, but when inserted into the water, I can't get it over 4,000 RPM and it occassionally overheats. The engine appears to be fine, the only thing I can imagine is that being out of alignment, it's overworking the engine when turning the prop. It just seems strange I don't get the same vibration that others have experienced.

Thank you in advance,

NH Moomba
07-26-2004, 09:52 PM
I just did the alignment thing on my 2000 LS and it was a piece of cake. Brian Raymond faxed me an instruction sheet. The hardest part was getting the darn prop shaft cover plate out from under the rear seat. The directions say to remove the seat but on the LS, that leaves a big fiberglass base behind that doesn't look to come out easily. After separating the flanges, the drive shaft had a "natural" position that was offset from the transmission by nearly 1/16 of an inch. The motor slid over easlily enough with a prybar and then it just required one turn of a front jack screw and everything was perfect. I can't believe how much smoother the boat feels. After putting it all back together and taking a test run, the boat suddenly lost power and would not accelerate. Assuming we had messed up something, we were checking out the engine when smoke started coming out of the exhaust. My heart almost stopped. We then noticed the temp guage was at 240 and shut it down. The impeller had smoked. I am assuming it was a coincedence that it happened at this time. I am wondering if the fuel injection computer was limiting the power due to the overheating? Luckily I had a spare and were back in business in 20 minutes. Hopefully I didn't damage anything.


07-27-2004, 09:01 PM
Good luck there with the impeller.

That can cause partial loss in cooling, also.

Regarding pictures, I literally dropped my wife's camera into the bilge when taking the third photo, destroying it.

Put the boat back together long before I replaced the camera. Sorry, usually I follow through.

Its not a difficult job. Get the factory assistance mentioned and go for it.