shaft/engine alignment

[gloucestersailor]

I installed a moyer rebuild this season and it is running great. I had a little problem with the alignment.

I have nudged the engine back and forth, and the couplings appear to be in perfect alignment.

Try as I might, I cannot remove all the wobble. (I see the shaft log hose wobble as the shaft turns) It is slight, but clearly still there. Is a little wobble ok or must all wobble be removed?

Gloucester Sailor

[Don Moyer]

It's rather unusual for the couplings to line up perfectly and still have
observable run-out (wobble) of the shaft in the area of the stuffing box.
My guess is that there might be a small (almost imperceptible) amount of
bend in the prop shaft.

The big question is whether or not you feel any vibration when the engine is
running in forward. If the engine and drive train run smoothly in forward
at your favorite cruising RPM, you're probably OK. If you feel vibration
and/or the shaft does not spin freely when turning by hand, I recommend
having the prop shaft checked by a local machine shop.

Don

[Norman Johansen]

I also have a shaft alignment problem. I have sheared off 2 sets of shaft coupling bolts and keys and the shaft backing of the coupling in the last 3 weeks this year and it happened last year too. The shaft seems to be running true thru the stuffing box. There is a squeaking noise and vibration which seems to be coming from the cutlass bearing and prop area. The boat (Islander 33 sailboat) was hauled this week. I discovered the Indigo 3-bladed prop was severly damaged by electrolysis after 3 years in the water year round. The prop damage could have caused by the boat not having any zincs installed due to lack of room on the shaft. The damaged prop could have caused the bolt-key shearing problem. The cutlass bearing seems to have a little wear after 6 years and seems to have only minor 'play' when the shaft is pulled in any direction by hand. I plan to install a longer 3/4" shaft, new cutlass bearing, 3-bladed Indigo prop, PYI packless sealing system (stuffing box).

Question: Would and out-of-balance prop cause the shaft coupling bolts & key to shear off in a short period of operation?

Has anyone had any negative experiences with the Indigo 3-bladed prop and/or the PYI packless sealing system?

[Don Moyer]

The addition of zincs on the prop shaft should prevent future deterioration of your prop, but I'd check in with Tom Stevens of Indigo Electronics just be sure there isn't some other issue to consider. His phone number is 1 (800) 428-8569. We've never heard of any issues with the PYI packless prop sealing assemblies. We've had two of them on previous boats.

Don

[Norman Johansen]

Has any Atomic 4 - sailboat installed user reported the shaft coupling bolts and key shearing problem I have been experiencing? After removing the shaft and coupling this weekend, I found that there was considerable amount of 'play' in the engine transmission coupling to shaft fit. This union was a snug fit when installed last July (2005). This is the 2nd coupling that has been installed since the remanufactured Atomic4 was purchased from Moyer Marine in Oct 2004. Again the coupling seems to be running true and there is no evidence of wobble at the stuffing box. I am going to try to realign the engine, install a new shaft coupling, 3/4"shaft, cutlass bearing, and Indigo 3-bladed prop. I am also considering drilling a hole thru the coupling and shaft and installing a bolt and nut to keep the shaft from backing out of the engine while running in reverse at 1200-1500 RPM which has occurred often over the last several years. Do you see any problem with installing a bolt in the coupling and shaft? If this is feasible, what is the recommended bolt thickness and metal composition (e.g. stainless steel, or other compatible tough metal). Thanks for you quick reply.

Norm Johansen
Annapolis, MD

[jimjuliem]

I was glad to hear Don's response. I have a very minor wobble and wasn't sure what to do about it. I guess I don't understand the usual instructions for measuring shaft alignment with a feeler gauge because there isn't any distance between my two flanges that connect the shaft to the transmission. Then I saw a power boat site that said you have to disconnect the two flanges to see and measure the alignment. That made more sense. Here is my question: Do you have to disconnect the shaft from the transmission to measure for proper alignment?

[jhwelch]

I went through this process recently; my engine needed to be
moved quite a distance so there was a lot of shimming and
shifting involved.

You need to disconnect the coupling that is attached to the
shaft that runs back to the prop. from the output plate that
is attached to the tailshaft coming out of the engine.

I found my coupling must have been machined at some point
in the past, as the best fit occurred when it was rotated into
a certain position that matched up with the output plate from
the engine.

If you can, use a come-a-long if you think you need to lift and
shim the engine. A helper is another good thing to have. :)

-jonathan

[jimjuliem]

Thanks for the information!
I copied it and will put it in my maintenance manual.