"trainfan1" wrote in message
et...
F.H. wrote:
trainfan1 wrote:

I owned/piloted & worked on many jet boats.

I owned/piloted *one* jet boat and its been about 20 years. I *know*
about the flatbottoms, (prop type) I built them for myself and others as
well as raced them but my memory could be playing tricks on me with
regard to how pumps are set up. The idea with a Day Cruiser was to
*avoid* wrenching. I do seem to recall a spline back there and I know
that some way of allowing for slight misalignment is necessary.

Engine mounts are on adjustable screw mounts / trunnions.

http://marineengineparts.com/shopsit...dia/8-0008.jpg
http://marineengineparts.com/shopsit...ia/4417224.jpg

Alignment is done with a feeler gauge at the output flange and the
propshaft flange. It's fun. No u-joints.


What is a Poly isolation coupling? Does it have a spline like a drive
shaft?

"Rubber Damper":

http://www.pronautica.com.br/exporta...%20003_206.gif

It goes inside the two halves of a jet-drive coupler:

http://www.legdrag.com/images/ADA%20800%20Couplers.jpg
http://www.pronautica.com.br/exporta...%20003_216.jpg

for isolation & allowing for slight misalignment . No u-joints.



I'm looking for the brand Boat or drive/pump - that has u-joints.

You mean you're in the market?

You mean there are none?

Rob

Mine is a Jetcraft 21' Aluminum jet boat. With a 3 stage Kodiak pump.
Original power was a Ford 351W now a 350 MPI Chevy based engine. Has a
Spicer coupler with 2 U-joints. U-joints must always be used in pairs
otherwise you get a speed change on the output shaft during rotation. All
the Aluminum jet boats use basically the same setup, except for the engine
forward design and they use a jackshaft. We also adjust the engine, so
there is very little miss alignment. The splines are so if there is any
flex the shaft can move as well as side benefit easy way to pull the shaft
if needed.