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Drive shaft alignment


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  • Baller

2005 MC 197 non-slot

I thought I had a bent drive shaft because I could see it wobling at the packing seal and if I held a screwdriver tip against it while in gear at idle you could see and feel that it wasn't true.  I even checked it without the prop installed and it still wobbled.  When I pulled the shaft and rolled it on a granite countertop it appears to be true.

I hit a turtle last year and had the prop re-done by OJ. I'm wondering if it also bent the skeg?  I was going to re-install the shaft and check the alignment but I have some questions on how to verify it.  I understand that you install the shaft and check the coupler to transmission around the coupler in 4 places with a feeler guage.  What is the procedure before you measure as when the coupler is tight there is zero clearance?  Do you start to tighten the bolts and when you get close to tight but can still get the feeler guage in do the measurement and alignment?  After alignment you then pull it tight?

 If the skeg is bent is aligning the engine to match it  a problem as long as the shaft is relatively straight throught the hull exit opening?

 Also, the washer that holds the o-rings in the shaft seal wore a grove in the shaft.  It's as if the engine is lower than it should be and pulling the seal and short hose section down.  I'm thinking I should order a new washer but is there a more flexible alternative to the short piece of hose which would alow the seal to float easier?

 And lastly, does the engine need the alignment regularly adjusted over time?  If so what is causing it to move, motor mounts wearing out?


Rod A. 

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  • Baller_

To check the shaft alignment for squareness:  have the coupler free but pull up to flange, check the clearance to see if you can get a feeler gauge in the side opposite the side you have closed the gap between the coupler and flange.  You can also loosen three bolts completely, one just slightly then when separated measure the gap on four fastener positions and the difference is the gap.  Prior to that, you will want to check to make sure that the vertical and side to side to side position is aligned correctly.  On this one, you need to basically feel the correct free position of the shaft and coupler to ensure correct position, you will need to take out the effect of weight drooping the shaft slightly. 

If the lock tabs are not bent over to keep the lower locking nut fixed on the engine mounts, the engine can lower itself over time if the nuts spin, which is possible.  Bending the shaft support strut can also create a misalignment.  Another way to check alignment is to use one of the laser levels or even one of those temp probes that uses the laser and shoot it thru the shaft strut to see if it hits the coupler in the center, that will give you a ball park start.

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