Engine alignment on O'Day 28

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R

Rag Doll

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Sep 3, 2011
59
O Day O Day 28 Michigan City, In.
My question is, should Shaft to Engine alignment be made with the boat in the water or would it be acceptable while it is on jack stands? Are there stresses on the hull while it is on jack stands that would give me a false prealignment reading. Is the alignment better to do with the boat in the water when all stresses are delivered over the entire bottom of the boat? The jack stands are placed under the hull at the bulkhead location in the cabin.

I have an O'Day 28 with a Universal M12 Diesel Engine. I am going to change the packing of the shaft log before attempting any alignment while it is on its jack stands. I have replaced the strut bearing, the strut is firm and secure. :doh: Any suggestions!!!!!
 
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TLW

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Jan 15, 2013
271
Oday 31 Whitehall, MI
The O'day manual tells you to do this in the water. They also indicate that the shaft should be uncoupled before you take it out of the water. All that being said, few owners or yards seem to follow this advice.

You probably need to motor immediately after launch, so an alignment prior to launch and repeating the process a week or so after the boat is back in the water is the practical approach. The boat can take a while to regain its in-the-water shape.
 
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Barnacle Bill

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Jun 9, 2008
1,801
- -- -Bayfield
In order to align a shaft, you have to have it rotating. Easier to do that in the water (so that you don't overheat your engine - its a pain to keep feeding it water when on the hard). The best way is to have a dial gauge to put on the shaft as it is turning. That will tell you exactly how out of column the shaft is.
 
anchorclanker

anchorclanker

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May 27, 2012
1,152
Oday 222 Beaver Lake, Arkansas
Yanmars manuals says you to align the shaft coupling with the engine NOT running and with the couplers unbolted from one another. You slide the two coupling halves together without bolts to check basic visual alignment, and adjust engine as needed so they come together squarely with the prop shaft visually centered in its packing. Then you start using feeler gauges between the two halves at 4 points 90 degrees from one another around the couplers circumference (top, bottom,left, and right), and fine tune engine mounts as needed until your as close .000" difference as you can possibly get. Maximum misalignment at the couplers is .02mm (.0007"). Misaligned couplers will cause vibrations at the very least.

Checking the running shaft with a dial indicator would test for a bent shaft, but is not the correct way to check for coupling alignment. Fiberglass boat hulls deform out of the water or lifted by sling, which is why you should follow the advice given above by TLW, to recheck alignment after a few weeks. Always refer to the proper manuals.
 
T

TLW

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Jan 15, 2013
271
Oday 31 Whitehall, MI
Trying to align the shaft on a running engine is a good way to get seriously injured. Please follow procedures recommended by manufacturers, and numerous books/articles on the subject. Anchorclanker outlines the correct procedure.
 
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Boatsail1

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Jul 30, 2012
43
O Day 28 foot Fernandina Beach
Great information. Did not realize it was this involved and potentially dangerous. Thanks and good luck.
 
anchorclanker

anchorclanker

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May 27, 2012
1,152
Oday 222 Beaver Lake, Arkansas
Its not dangerous done the way the manuals explain it. The manual should be the first tool we reach for, not the last. Sadly, most never reach for them at all.
 
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Rag Doll

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Sep 3, 2011
59
O Day O Day 28 Michigan City, In.
anchorclanker said:
Its not dangerous done the way the manuals explain it. The manual should be the first tool we reach for, not the last. Sadly, most never reach for them at all.
Click to expand
TLW and Anchorclanker thank you for the information. I should have consulted the Engine Manual before asking the question. I have not been having vibration problems or any transmission noise/heating problems but thought it wouldn't be a bad idea to check the alignment anyway. I'll wait until the boat is in the water before checking the alignment and hopefully there are no issues. I had bought the boat in 2009 and haven't had any issues except a electric fuel pump to replace so if I continue to monitor the regular service routeen I can catch problems before the cost more then I want to think about.

Thank you ALL again for your information, cautions and reminder to always go to the service manual first.

Rag Doll
 
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