Flexible coupling

[mcca]

Can anyone advise or recommend a suitable flexible couplings also would be good to hear some feed back of others who have fitted them and if they saw a reduction in vibration.

[KWKloeber]

More info?  Is the cause your coupling or your engine mounts (isolators)?

[David Sanner]

I added one of these http://www.pyiinc.com/flexible-shaft-couplings.html  which was pretty easy to install (I had to cut the shaft down but had enough key left to use original shaft setup) and wasn't that expensive.   It also provides some shock load reduction and electrical isolation.

It helped a little bit with vibration (not as much as installing soft engine mounts).

I think it might also reduce the stress on the cutless & dripless elements when using softer engine mounts.
Finally supposedly helps a little bit with mis-alignment ... but engine should be reasonably aligned.

[sailaway]

flexible coupling doing solve vibration problems. They might help a little bit but the root problem is still there. Charlie

[Bill Shreeves]

This is my second season after installing a Federal flexible coupling.  I love it.  By the way, no need to change the length of the prop shaft with this coupling.

http://www.federalmarinetransmissions.com/100101.html

[Roc]

I also have the Federal coupling.  Love it too.

[Dale Stone]

David,
Why did you need to cut the shaft down? Thought the PYI didn't take up that much length. Thinking about the Federal too.

[Roc]

I have the PSS dripless seal and the Federal Coupling fits.  The Federal Coupling is a true flexible coupling.  Unlike the PYI "drive saver" which says that it acts like a flexible coupling, but it's design is really intended to be just that, break away if you hit something. 

[Dale Stone]

Thanks Roc
I have the dripless as well on a 2001 MK II. If I spend the time and money, I might as well go with a true flex coupling. The PYI is less than half the cost of the Federal, however I would want some vibration reduction. Do you have the Federal spec on yours? And there is no need to modify the shaft?

[Dale Stone]

Got the price wrong, the Federal is less than $250 and the PYI is less than $200. I think the correct Federal is a 43A.

[Bill Shreeves]

My only concern would be whether or not you can remove your existing coupling.  I was unable to remove mine from the original bronze shaft despite lots of penetrating oil, some heat / cooling and building a coupling extraction tool out of steel plate with hardened bolts/nuts to extract it from the shaft.   i gave up after seeing the 4-1/2" square 3/8" thick plate bent from excessive pressure and realized, for me, it was a lost battle and I cut out the shaft.   I thought a nice shiny new SS shaft would've been a nice addition anyway and, it was.   I had the new coupling mated to the shaft for a palm press fit by the company that made the shaft.

Hope this helps...

[Dale Stone]

Hi Bill
I installed a shiny new SS shaft last spring. I should be able to get it off without much grief but understand why you had an issue. I ordered the Fed Flex yesterday and had a long discussion with James who has worked at Federal since the late 60's. These flex couplings have been around since the late 50's. He said the trunions should be replaced every 10 to 12 years. Also he discussed the key and set screws positions.

Looks like they can be different for different boats which means new spots on the shaft are required if they don't line up. I have not read that anywhere in many discussions since I've been looking.

The price list I had is old. The Federal 43A for our boats are $315.00 and grounding straps are $10.00 each.

Thanks
Dale

[Bill Shreeves]

Dale, thanks for the info.  The design of this coupling appealed more to me than any others and appears to be both flexible and very durable.  I too had a good conversation with Dale however, he didn't mention trunion replacement every 10 years or the availability of grounding straps.  I've recently thought more about grounding and I think I'll call and order what they recommend.  Thanks!

[Dale Stone]

His name is James Aspel. He answered the phone and I found him very informative. He explained the rubber gets hard with age. And since some of these have been around since the 50's, he sees 30 to 40 years units with the original rubber.

Federal 708-352-2200