Propellers have two basic dimensions; diameter and pitch.
Diameter is the distance measured across the propeller hub line from the
outer edge of the circle that is made by the propeller's blades during
rotation. Pitch is the distance that a boat will travel if rotated one
revolution without any slippage. When describing a propeller both the
diameter and pitch are given. The diameter is referenced first and the
pitch is second. Therefore, a 12" x 9" propeller would have a 12-inch
diameter and a 9-inch blade pitch.
Theoretically, a propeller with a 14-inch pitch, when
rotated one full turn, would advance a boat 14 inches through the water.
In reality, no 14-inch pitch blade will advance a boat 14 inches with
one full turn. This variance is referred to as slippage.
In general, changing to a higher pitch prop will
increase your top-end speed but reduce your acceleration (reduce your
"hole-shot" power). On the other hand, decreasing the pitch will
increase your hole-shot but sacrifice some of your top-end speed. If the
hole-shot speed is important to you, for example if you pull water
skiers most of the time, then you would want to go with a lower pitch
prop and sacrifice some of your top-end speed but increase your
hole-shot speed to get the skiers up faster.
UNDER NO CIRCUMSTANCES SHOULD YOU EVER USE A PROP
WHICH WILL ALLOW YOUR OUTBOARD
TO OPERATE ABOVE THE OUTBOARD'S RECOMMENDED MAXIMUM RPMs!
propeller selection chart can be used to help you in selecting the
correct propeller for your Tohatsu outboard. Remember that in any
application, discrepancies in performance can result due to the
different boat hull designs, the final carrying load and your particular
It is highly recommended that the outboard be checked with a tachometer
to ensure that the engine is operating within the correct MAXIMUM RPM
selection of the correct propeller will allow the engine to obtain it's
full RPM as well as the designated horsepower. Engine horsepower is very
closely related to the RPM that the outboard can obtain. In other words,
if the outboard can not reach its specified RPM, it cannot reach its
specified horsepower. We hope
that this selection chart helps you in making the right decision when
choosing a propeller for your Tohatsu outboard.
PROPELLER HARDWARE KITS
MFS4/5/6A & A2 & B & C
MFS8/9.8A & A2 & A3
MFS9.9/15/18/20 B & C
MFS25/30A & B
Propeller Hardware Kits include the thrust holder, washer, nut and split
kits for models not listed, please contact your local dealer.