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View Full Version : What's the correct Shaft Angle/Strut for an 87 ProStar 190?


pdiprete
08-24-2007, 11:33 AM
Folks:

This may sound weird, but I think my boat has the wrong strut. The shaft is *never* easy to turn (always take a good grip on the prop, sometimes with 2 hands). What I noticed when testing props last weekend (before I dropped my cell phone in the (salt) water was that the prop shaft does not pass "straight through" the bore in the strut. That is, it's not parallel to the bore. At the rear, the prop shaft is near the top of the bore (like 1mm away from the strut itself).

I heard a rumor that MC changed the angle from 14 to 15 degrees way back when. What are the chances I have the wrong strut? How do I identify / buy the correct one?

Thanks to anyone who unlocks this mystery. I'm betting all my noises (except for the good ones :D ) go away, when I get this right. Noises? Growls loudly on takeoff and has a nasty noise at slalom speed (somewhere between a whine and a growl).

Cheers,
Peter

KHall
08-24-2007, 05:01 PM
Unbolt the drive flange bolts and check alignment. See if the motor/trans has room to adjust in the direction to center the shaft into the strut. Might only need to align the shaft to the strut, which still requires adjusting the motor and trans. Once strut is centered then adjust the flange to .003 max all around.

G-man
08-24-2007, 06:12 PM
The prop strut and shaft packing determine the angle, the engine gets aligned to the shaft not the shaft getting aligned to the engine

pdiprete
08-25-2007, 03:16 AM
Guys:

Since 2 points determine a line (grammar school geometry), and since there are 4 points along the shaft (flange, packing, strut entry and strut exit), please grant me that the shaft could be aligned with the engine (per the usual alignment technique), and the strut could still be "the wrong angle". This is what I think is going on.

The engine *is* aligned properly. (Maybe I'll double check on Sunday.) Still, there is a lot of resistance, and it "doesn't look right" at the strut.

Please don't give me an education in alignment, been there, done that, but if anyone knows something about the problem I'm reporting, then I'd *love* to hear about it. If MC never changed the shaft angle, then I don't know *** is going on.

Cheers,
Peter

KHall
08-25-2007, 08:40 AM
I'am saying this because i just went through this. It is possible to align motor to shaft and have it all alittle missaligned with respedct to the strut. My motor was aligned to the shaft flange and still did not spin correctly.

Now i can spin my prop with my finger, while dry. I'am also using less gas than ever.

H20skeefreek
08-25-2007, 08:56 AM
Guys:

Since 2 points determine a line (grammar school geometry), and since there are 4 points along the shaft (flange, packing, strut entry and strut exit), please grant me that the shaft could be aligned with the engine (per the usual alignment technique), and the strut could still be "the wrong angle". This is what I think is going on.

The engine *is* aligned properly. (Maybe I'll double check on Sunday.) Still, there is a lot of resistance, and it "doesn't look right" at the strut.

Please don't give me an education in alignment, been there, done that, but if anyone knows something about the problem I'm reporting, then I'd *love* to hear about it. If MC never changed the shaft angle, then I don't know *** is going on.

Cheers,
Peter
If the cutlass bearing is worn b/c of a mis-aligned shaft, then you align the motor to the shaft, it will still be out of alignment. Regardless of your strut angle (we are talking about 1*) with a fresh cutlass bearing, the engine could then be aligned to the shaft, making the shaft spin efforlessly.

wesgardner
08-30-2007, 09:31 AM
H20skeefreek - Bingo! (Probably)

The strut (actually the cutlass bearing within the strut) should be the thing determining shaft angle...yes there are two points on the line - one where the shaft enters the strut and one where it exits - all within the length of the cutlass bearing (about 4-5") the stuffing box/packing gland/whatever you wanna call it should NOT have to be forced into position - the shaft should slip right up thru the stuffing box and butt up against the backside of the trans. (once you've put the coupling on) If this is not the case, maybe the strut's bent...
THEN you align the motor to the coupling/shaft

If you think the strut "is at the wrong angle" you could pull the stuffing box completely loose from the shaft log/stern tube and see if the shaft aligns with the backside of the trans. (it should...) - you might have to support the shaft a little due to the long cantilevered distance between strut and motor

pdiprete
08-30-2007, 12:03 PM
Thanks, Wesgardner, I guess I'll pull it apart this weekend. I figure when I do this, I should:
- pull the boat out of the water (don't want to be doing this on the hydrohoist)
- pull the shaft
- replace the cutlass
- realign, starting with the strut as you said
- I'll loosen everthing along the way to see where it's actually out of alignment

Of course, now I have to buy the shaft / bearing puller and new bearing. I'll replace my stuffing box with one of the dripless variety (anyone have experience with OJ Prop's XPC ceramic bearings?).

Thanks again,
Peter

Tom023
09-01-2007, 09:27 AM
Last year, I replaced my cutlass bearings and log with the XPC ones from OJ. The drivetrain is noticeably smoother and it was nice to have a dry bilge. I say "was" because this year the shaft seal started leaking. A call to OJ and I quickly had a new seal! They are a good company and stand behind their product. I still have not installed the replacement so I cannot tell why it failed, but overall I am please with the product and the company support.

pdiprete
09-02-2007, 03:07 AM
Tom:

That's good to know. I'll do that over the winter. Did you do it yourself? Easy?

BTW: I also fly (should say, I have also flown) the Tiger. Love it.

Cheers,
Peter

Tom023
09-02-2007, 10:47 AM
Pulling the shaft is the hardest part of the install, which really isn't that difficult. Be sure the shaft is in perfect condition where the seal will rest, or that could be cause for a leak. Also, do not remove the cardboard insert the seal is shipped with until just before installation. Come to think of it, MC starting using these seals as standard equipment a few years back and I think they have held up exceptionally well, so my leak I'm assuming is a very rare occurence.

Tigers are great planes!