2006 Johnson SD 3.5 HP 2 Stroke Outboard Service Manual, PN 5006562, Page 37Get this manual
INSTALLATION AND PREDELIVERY
PROPELLER SELECTION
PROPELLER SELECTION
Refer to PROPELLER on p101 before installing propellerThe correct propeller, under normal load conditions, will allow the engine to run near the midpoint of the RPM operating range at full throttleRefer to TECHNICAL DATA on p18
Procedure
The propeller selection process is very important to the engine's service life and to boat performanceProceed carefully and thoroughly while considering the following points: During the engine break-in period, run the outboard at wide-open throttle for only brief periods of time to check full-throttle RPM Use an accurate tachometer to determine the engine's full-throttle RPM while testing various propellers Select propeller that suits the customer's application and allows the engine to run near the midpoint of the full-throttle operating range when the boat has normal load in itRefer to TECHNICAL DATA on p18 To compensate for changes in boat loading, the engine's full-throttle RPM must be verified periodicallyIMPORTANT: If the propeller blades have too much pitch, the engine is operating below its normal range at full throttle, power is being lost, and powerhead damage could occurIf the propeller blades have too little pitch, the engine is operating above its normal range at full throttle and damage from overspeeding could occur