Selecting A Propeller - Indmar 5.7L Vortec Operator's Manual

!
Carbon monoxide gas (CO) is colorless,
odorless and extremely dangerous. All
engines and fuel burning appliances produce
CO as exhaust. Direct and prolonged expo-
sure to CO will cause BRAIN DAMAGE or
DEATH. Signs of exposure to CO include
nausea, dizziness and drowsiness. Ensure
adequate ventilation to prevent accumulation
of CO in the boat.
Monitor the engine temperature gauge frequently. If your
engine overheats, carefully inspect the exhaust hoses for
damage. Damaged hoses can allow carbon monoxide
gas to enter your boat.

SELECTING A PROPELLER

For best engine performance and longevity, the wide-
open-throttle (WOT) engine operation must be near the
top of, but within, the specified WOT operating range. To
adjust the WOT operating range, you must select a pro-
peller (propping) with the proper diameter and pitch. The
propeller which was supplied with your boat was chosen
by the boat builder for best all-around performance
under average conditions.
4-8
Load, weather, altitude and boat condition all affect
!
WOT engine operation. If you use your boat for several
different applications such as wakeboarding, barefooting
and cruising, it may be necessary to have 2 or more pro-
pellers which will allow the engine to operate in the WOT
range for each application.
Propping the boat should be done after engine break-in
and the initial 10 hour dealer check. The boat should be
loaded the way it would normally be for each application.
For instance, if you are propping for wakeboarding, fill
the ballast tanks if equipped and add all the people and
gear you would normally expect to carry in the boat.
Take the boat out and after warm-up, run it at wide-open-
throttle and note the maximum RPM. EFI Engines are
equipped with RPM limiters to prevent over-revving. Take
note if the RPM limiter is activated.
If the WOT RPM is higher than the maximum RPM in
your engine's WOT operating range, the boat is under-
propped. Install a higher pitched propeller to reduce
WOT RPMs. An engine that is over-revving may quickly
experience catastrophic damage.
If the WOT RPM is lower than the minimum RPM in your
engine's WOT operating range, the boat is over-propped.
Install a lower pitched propeller to increase WOT RPMs.
Indmar Marine Engines