By process of elimination, it pretty much has to be something
slipping. That high pitched noise suggests a clutch. It could be as
simple as the shift cables being misadjusted so the clutch isn't fully
engaged. Unfortunately, if that is true, the transmission is probably
going to have to come out of the boat because the clutch surfaces are
glazed.

First thing to check: Cable adjustment for full travel on the lever
at the transmission. If cable adjustment fixes the problem, the
transmission is still probably on borrowed time. Don't depend on it
in a tight spot.

Next: What RPM do you get in reverse? Marine transmissions usually
have two clutches and the reverse one is unlikely to be damaged. If
maximum RPM in reverse is significantly less than when bringing it up
to full power in forward, the engine is being loaded up more. That
probably means the forward clutch is slipping. This test is hard on
the engine so just do it once and with a well warmed up engine.

You can buy or rent tachs that read a little bit of reflective foil
taped to a shaft. Check engine RPM at the flywheel to be sure the
tach is right. Then check the tach against shaft RPM.

If you verify slipping, be sure the key is still in the shaft coupling
before you pull the transmisson out of the boat. Shaftlines have been
put together before with the key missing. The set screws can wear a
groove around the shaft so it won't back out and feels tight to the
hand but the shaft will slip in the coupling. A mark or piece of tape
on the shaft will reveal this pretty quickly.

A missing key on the prop could also be overlooked since the taper
will keep the prop tight and turning until it is heavily loaded. That
could also make your high pitched noise.

--

Roger Long



"Dennis" wrote in message
ups.com...
Hi Roger and everyone who replied!

Thanks so much for the constructive feedback!

Couple of points to clarify:
- I forgot to mention, the gear ratio is about 1:2.06 (can't read
the
label on the gearbox)
- I recently had the bottom done completely - it is as smooth as it
gets.
- I also had the propeller checked by the manufacturer and they
confirmed that the pitch is what it has been manufactured at.
- I have a brand new shaft and coupler and these are properly
connected.

So, I guess my best bet is to check the transmission. Now, how do I
do
that?
- Can I check the clutch/transmission without disassembling
everything?
Any ideas?
- Can I check and repair the transmission without hauling the boat
out
of the water?
- I also notice that there is a very high pitch noise from the
engine
after about 3700rpm until the max. rpm. Could that also indicate a
toasted transmission?

Thanks again!
Dennis