Raider Outboards R40ES-002, Owner'S Manual

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Raider 40 HP
SECTION 2
Owner’s Manual Standard Operating Procedures
30
P
ROPELLER
S
ELECTION
A propeller must be selected so that the engine rpm measured at wide open throttle while cruising is
within the max. operating range; 5,140 to 5,840 rpm.
Mark
Propeller Size (Diameter Pitch)
Inch mm
Heavier Load
Lighter Load
7* 11.4x7.1 290x180
8.5 11.2X8.7 285x220
9 10.9X8.9 276X226
10 10.8X9.9 275X252
11 10.6X11.3 268X287
12 10.6X11.7 268X296
13 10.3X12.7 262X322
14 10.2X13.9 260X352
*Indicates a four (4) blade propeller
The pitch of a propeller is defined as "the distance a propeller would move in one revolution if it were
moving through a soft solid, like a screw through wood." For example, a 15-pitch propeller would move
forward 15 inches in one revolution.
The lower the prop pitch, the better your hole-shot. However, this comes at a price: top speed. The lower
pitch makes the engine reach maximum rpm at slower speeds. Conversely, a higher pitch will deliver
greater top speeds, but slower acceleration.
If you're changing pitch, remember that each inch of pitch is worth about 200 rpm. Lowering the pitch
will increase rpm and vice versa. For example, going from a 11-pitch to a 13-pitch propeller will increase
engine rpm by about 400 revolutions.
The trick is to choose a propeller that delivers acceptable acceleration and top speed. Perhaps what's
most important is your performance goals, either deliver low-end torque or faster top speeds, you can't
have both. If you load your boat with tons of gear, you might need a low pitch. If you need more speed,
a higher pitch is the way to go.