Bullflex coupling

[Bruce Hanson]

I would like to submit one more strong vote for the Bullflex coupling. I installed one last weekend and it made a larger improvement than the K-75 engine mounts installed last month. Alignment was more difficult due to the bulk of the unit however it is obviously not as important now.

I was just able to slide unit on the shaft without removing the exhaust from engine. Using the vang attached to the boom worked great, had to separate the mounts from the cradle in order to kind of rotate engine while raised to the maximun allowed by the exhaust. 

New Gore packing is running hotter than I like however I need to research this data base for more information (after 20 minutes at 2600 was to hot to leave my hand on)

[Ron Hill]

Bruce:  Important things first, somethings wrong with your packing installation!!  Too hot if you can't keep your hand on it.  Try to back off the gland nut as it's probably too tight. You should have only tightened it only HAND tight to start off with and then tightened it a 12th of a turn at a time until the water stops dripping.  Let us know if the backing off works.

Anyone that plans on installing a Bullflex or any other flexible coupling, MUST get the engine shaft alignment as close as possible with the hard coupling FIRST, in the water for at least 24 hrs with the rigging tuned(tensioned).  It's a great item for never having to worry about alignment again.
M35 owners, you'll need a different flexible coupling as you don't have the room for a Vetus Bullflex coupling (your 4th cylinder takes up the extra space).   

[Mike Vaccaro]

Bruce,

Ron's right--the Bullflex doesn't relieve you of the need to properly align the engine.  You can align it with the Bullflex, just like a normal coupling.  Should strive to get each "point" of the transmission fitting (4 total) within .003".  Where the Bullflex pays dividends is in reducing overall shaft vibration, which is translated directly to the hull.  The more out of alignment a Bullflex is, the lower the maximum safe RPM it may be run at.  Combined with proper motor mounts (-50's or -75's), it eliminates a substantial amount of vibration compared to a factory installation.  It does require an occasional treatment with some type of corrosion preventative coating that is rubber friendly, since it is made of steel (although most components are anodized)--especially if you use an old-fashioned packing gland that occasionally slings some water in that area. 

Your packing should be warm at normal operating temperatures, but not too hot to hold.  Might want to start with hand tight and then monitor during an engine run with the aft berth access plate removed.  There is no harm or foul if a small amount of water ingresses during operation.  Over time, packing compresses and you must occasionally adjust the nut.  With a conventional bronze packing gland, it's a good idea to occasionally clean it and treat it with some type of corrosion inhibitor--makes it easier to adjust the nut over time if you keep it in good shape.  Have had good luck with an occasional rub-down with Lanicote or a spray of Boeing T-9. 

Cheers,

Mike