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AZDave
07-22-2013, 01:18 PM
I have a 93 ProStar that has always had some vibration. The coupler gap was checked a few years back, and I have added a 4 blade. It runs pretty smooth compared to other like Mastercrafts. The packing is origional, and the raw water pump new, and vibration free. No play in the strut. 700 hours. Any tips out there on fine-tuning this to a little less vibration.

mikeg205
07-22-2013, 02:11 PM
Is shaft with .003 of being straight - has that been checkd?

AZDave
07-22-2013, 04:28 PM
No. Is there an easy method to check this? Do these things warp over time? I heard of a similar boat with a slot break off at the prop. I inspected the end for any cracks.

mikeg205
07-22-2013, 05:11 PM
not hard - just need one of these.

here's the tool -- yes I know it's harbor freight - ;)

http://www.harborfreight.com/1-inch-travel-machinists-dial-indicator-623.html

i know it's not a prop shaft but it works

here's a video http://www.youtube.com/watch?v=jtlPTJSNfwo

thatsmrmastercraft
07-22-2013, 05:16 PM
not hard - just need one of these.

here's the tool -- yes I know it's harbor freight - ;)

http://www.harborfreight.com/1-inch-travel-machinists-dial-indicator-623.html

i know it's not a prop shaft but it works

here's a video http://www.youtube.com/watch?v=jtlPTJSNfwo

Good Answer! (http://www.youtube.com/watch?v=RYDsI5mP-V8)

mikeg205
07-22-2013, 05:17 PM
Good Answer! (http://www.youtube.com/watch?v=RYDsI5mP-V8)

Why.... thank you Peter... :) -- learned much of MC everything here on this fine forum from the great people here...

thatsmrmastercraft
07-22-2013, 05:28 PM
Why.... thank you Peter... :) -- learned much of MC everything here on this fine forum from the great people here...

I have learned a lot here myself. Most people wouldn't realize checking your prop shaft is as simple and cheap as it is.

cruiser
07-22-2013, 05:30 PM
I did a lot of work on 30ft. plus chris crafts years ago with the same problems. If the shaft is straight, prop is straight and balanced and the key slot and key way are cut to proper depth. By this i mean put the prop on without the key in place and mark with a black marker, then remove the prop, install the key and replace the prop. It should go back on to the mark. If it does not you have to mark with hi-spot blue and scrape it in. If the prop does not go on to the same location, under load you can get a vibration from what we used to call Prop Wiggle.

AZDave
07-22-2013, 06:05 PM
I will try the dial indicator. I installed the prop using cruiser's procedure, Even did the whole prussian blue check. The dealer charged $100 to check the gap on the coupler. How hard is this?

Cloaked
07-22-2013, 06:09 PM
I will try the dial indicator. I installed the prop using cruiser's procedure, Even did the whole prussian blue check. The dealer charged $100 to check the gap on the coupler. How hard is this?
Not hard at all...
I presume your talking about the shaft coupler (to the trans)?
.

mikeg205
07-22-2013, 07:02 PM
I did a lot of work on 30ft. plus chris crafts years ago with the same problems. If the shaft is straight, prop is straight and balanced and the key slot and key way are cut to proper depth. By this i mean put the prop on without the key in place and mark with a black marker, then remove the prop, install the key and replace the prop. It should go back on to the mark. If it does not you have to mark with hi-spot blue and scrape it in. If the prop does not go on to the same location, under load you can get a vibration from what we used to call Prop Wiggle.

Interesting write up - I'll have to check this out...

AZDave
07-22-2013, 07:36 PM
Yes. It looks like you unbolt it and pry it apart, but there must be more to it.

AZDave
07-23-2013, 07:36 PM
Prop shaft ok. Coupler alignment at .010, tolerance .003 from manual. Slight vibration makes sense. Taking it to MC to adjust. Thanks for the help, I learned a lot...again

Cloaked
07-23-2013, 07:47 PM
What prop? CNC machined?

AZDave
07-23-2013, 09:35 PM
Acme 4 blade. CNC machined. When I installed it 7 years ago it helped smooth it out. When I put a new bushing on the raw water pump a few years back, that also helped. I think once the motor is aligned it should be pretty good.

Cloaked
07-24-2013, 05:16 PM
Acme 4 blade. CNC machined. When I installed it 7 years ago it helped smooth it out. When I put a new bushing on the raw water pump a few years back, that also helped. I think once the motor is aligned it should be pretty good.Call it good. Done deal....I'd run with it and be happy.....

.

TRBenj
07-24-2013, 05:21 PM
Misalignment will not cause vibration... it will dampen it. It will, however, cause your strut bushings to wear unevenly- which will cause a (greater) vibration once everything is aligned properly.

AZDave
07-27-2013, 04:46 PM
We will soon see. The boat was off about .010". Prop turns a little smoother now by hand. I guess if the vibration increases, the bushing will be the last thing to do. It is not like it ever had a severe vibration.

André
07-27-2013, 04:54 PM
Good video on shaft-engine alignement...
http://www.youtube.com/watch?v=3_w0LvD6gEc

AZDave
07-29-2013, 02:42 PM
Vibrating less following shaft to engine alignment. Very happy with boat operation now. Dealer said it was off. Took 20 years to need adjusting. I wish you could buy a brand new boat as simple and user friendly as these old ones. Hmmm, sort of like cars. Bells and whistles come with a price.