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Author Topic: shaft alignment with PSS shaft seal?  (Read 1621 times)

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shaft alignment with PSS shaft seal?
« on: June 09, 2008, 07:04:34 PM »

As some of you know from my previous postings I put in a new shaft, coupler, PSS seal cutlass and prop, now I'm looking at tuning the shaft alignment.

From what I understand, I loosen the bolts from the coupler to transmission, then what?

The local diesel mechanic is not a fan of dripless shaft seals, so I'm reluctant to ask him to align the shaft. I'm going to ask around for someone else. Is there something special to take care of with a dripless seal?

Pierre Comeau
Time To Keel, 1988 #687  Saint John, NB Canada

Ray & Sandy Erps

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Re: shaft alignment with PSS shaft seal?
« Reply #1 on: June 09, 2008, 07:23:22 PM »

The dripless shaft seal won't affect the alignment procedure.

When the seal was first installed, the installer should have checked to see if the shaft was centered in the shaft tube where the shaft exits the boat.  Once the PSS seal is installed, it's hard to check that while the boat is in the water without taking additional precautions to keep the boat from flooding.

Once that is taken care of the procedure I used was to back off on the couple bolts to give yourself a 1/4 inch clearance or so and slide the coupler apart.  Then slide the coupler back together until it touches.  Now slide a feeler guage around the circumference and look for gaps.  My recollection is that .001"/inch of diameter of the coupler flange is acceptable.  So if the couple flange is 3" diameter, .003 is good enough.  If it's out of spec, you use trial and error adjustments on the motor mounts to tilt the engine at different attitudes to bring it back in spec.  A large gap at the bottom of your coupler would indicate the front of the engine needs to go down.  A gap measured at the top of your coupler would indicate the front of the engine needs to go up.  A gap on either side means the engine needs to be slid sideways one way or the other.

That's the down and dirty method I've used. 
Ray & Sandy Erps,
'83, 41 Fraser "Nikko"
La Conner WA

Craig Illman

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Re: shaft alignment with PSS shaft seal?
« Reply #2 on: June 09, 2008, 08:19:06 PM »

Pierre - I got a lesson for a hour of diesel mechanic's time. Ray's explanation is the basic technique. Bring down a 15/16" (I think) open end wrench for the motor mount bolts and a friend to turn them for you while you check clearance at noon, three, six and nine o'clock. Make sure things are vertically aligned as well. The rear port mount is easier from the aft end.

The effort is worth it. I was on a older C36 this weekend that felt like it was going to shake apart at 2500 RPM.

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