View Full Version : Drive shaft alignment

01-04-2006, 07:58 PM
Anyone ever aligned a drive shaft. I have had a 'chirp' sound from my transmission area for the last year, going in and coming out of gear, forward or reverse. I split the coupler from the transmission and the shaft is completly all the way to one side. vertical aligment seems fine just the lateral offset???

01-04-2006, 08:26 PM
need more info

model, year, and motor

is it the one in your profile?

01-04-2006, 08:31 PM
Does the tranny run fine otherwise?Could it be the dampening plate?It's been known to do a funny noise when going in and out of gear and in low revs...Do a search here on transmission noise and dampening plate.

01-04-2006, 08:36 PM
he has a 02 197, according to the public profile. Is the answer going to be the same for my 91 ps190? I have wondered about this too. I have herd of it being done, but thought you had to have some kind of tool like on the front end of a car.

01-04-2006, 08:36 PM
here's a page from the downloads section for my 91 Prostar
here: http://www.tmcowners.com/teamtalk/local_links.php?

see attachment for my 91

two pdf's in one day.....looks like I'm ona roll:D

01-04-2006, 08:40 PM
Your all over it! :headbang: :woohoo: Thanks for the links.

01-04-2006, 08:42 PM
not a problem:)

you're gonna have to tell us a little more about the 302 roller motor:headbang:

01-04-2006, 08:43 PM
you want the truth, or what I tell everybody?

01-04-2006, 08:45 PM
you want the truth, or what I tell everybody?

good lord, you sound like my wife:(


01-04-2006, 08:58 PM
Hey! Well I always wanted a '91 ps 190 (since about 95) and couldn't find one in good shape. Found one after a couple years in perfect shape only it had a cracked head and about 1000 hours on it. Didn't want to rebuild the motor when what I really wanted was an efi motor. Wanted to go GM, but was told the tranny would not bolt up. Found this one at a marine junk yard with 45 hours on it and threw it in. Figured I could get more power out of the 302, and save gas than the stock set up. Then from playing with my buddy's 92 mustang knew a little about 302's (the last one we built has about 455 hp at the motor, no NOS), put small bolt on's like intake, then port and polish, port and polish the heads, mass air meter, bigger throttle body, and a couple small other things. Thought about doing more, but don't want to loose reliabilty or fuel. Has plenty of power! I think I will change a couple things back to stock to do a little better on gas though. Will still have more power than the stock 351.

Sorry to thread jack.

01-05-2006, 09:20 AM
I might have thought it was a dampening plate, but when I removed the 4 bolts holding the drive shaft coupling plate to the rear of the transmission the shaft went all the way (well as far as the opening in the hull) to the starboard side. I feel it is definetly a shaft alignment problem. I wonder if I should loosen the thru hull bolts, 6-8 of them, that hold the shaft 'support tower' and then try to move the 'support tower'...

the legend
01-05-2006, 10:09 AM
The gap between the trans coupler and the shaft coupler should be no greater than .003 -.005. You can move the engine up/down and left to right by adjusting the motor mounts and by loosing the two nuts on either front eng. mount located on the arm of the engine mounts.(brass in color) There are also one of these on the rear eng mounts. (brass in color) NOTE- remove (undo the two hose clamps and slide up the shaft) the packing gland when aligning, it will put pressure on the shaft if not moved out of the way. The alignment should take about 30 min. Remember to ck strut condition. Look at the strut bushings to see if the shaft has been riding off center.

01-05-2006, 10:25 AM
Hey Pilot,

The "shaft support tower" - is that perhaps the strut (the thing with the cutlass bearing in it?) If your shaft is that far out of line, maybe the strut is bent, or maybe the shaft is bent?

To clarify things - in a boat, you align the engine to the shaft, that's why the engine mounts are adjustable.

Bear in mind, if you do loosen the strut bolts, they ++COULD++ leak unless the strut is completely removed and rebedded (in 3-M 5200) if you want to do it any other way, be my guest, I've done lots of 'em...mostly on large cruising sailboats, sportfish, etc.,etc....and yes, folks have short-cutted it and ended up with a leak...that said, I don't know your situation, do you suspect a bent strut or what?

OOpps, just re-read your first post...if the vert. is OK then it ++COULD++ be a bent strut causing the shaft to favor the starboard side????

How much history do you have on this boat?


01-05-2006, 11:04 AM
I had to re align my '88 ProStar. I checked how much it would cost with my local MC Dealer (crooks!) and they said several hundred. I talked to a local boat mechanic and he did it for, if my memory is right, under $50

01-07-2006, 03:29 PM
Who's the local mechanic? When I put mine away in November, I opened the floor to grease the steering and it looked like my alignment might need attention again even though the dealer did the new shaft, strut and aligned it in August. :confused:

88 PS190
01-07-2006, 04:22 PM
Its easy enough to do yourself, but first check the shaft, if you turn a bent shaft the alignment should shift and not stay out to the one side. Also you should only be doing minor adjustments unless the engine has moved a large amount. The adjustment is done by using the engine mounts and then w/ feeler gauges judging the gap between the two flanges, if the gap is uniformly less than .003 around the shaft you are in alignment. So using the guage to check around the flange, then rotating the flange, and checking again you should be able to see if its out of alignment.

You seem to be mentioning a gross misalignment of the shaft w/ the transmission, so my first check would be w/ a tape measure and check the center of the engine, trans and shaft, and see if anything is shifted by a large distance.

01-07-2006, 04:31 PM
I have done alignments on direct drives and on my V-drive. Like other posters mentioned, start with the condition of the shaft and the strut first, the align the motor to the coupling. I noticed my strut bushing was wearing uneven and when I uncoupled the shaft it sprung over to one side like yours. Turns out my strut was bent. Bought a new strut and checked my shaft. Installed the strut and centered the shaft through the hole in the hull, then aligned the motor to the shaft. Helps to have an extra person when removing/installing the strut.

06-02-2006, 12:17 PM
Replaced the strut and aligned the prop shaft, now it is perfect!!! While I had it apart I installed the new MC dripless packing bushing - I can't believe it after 40 hours this year I have a completely dry bilge :-) I would highly recommend this if you have already got your shaft out...