Yamaha F25A Owner's Manual

Also see for F25A: Service manual Service manual Service manual Owner's manual Owner's manual

Contents

1-15EEMU01395PROPELLER SELECTIONThe performance of your outboard motorwill be critically affected by your choice ofpropeller, as an incorrect choice couldadversely affect performance and couldalso seriously damage the motor. Enginespeed depends on the propeller size andboat load. If engine speed is too high ortoo low for good engine performance,this will have an adverse effect on theengine.Yamaha outboard motors are fitted withpropellers chosen to perform well over arange of applications, but there may beuses where a propeller with a differentpitch would be more appropriate. For agreater operating load, a smaller-pitchpropeller is more suitable as it enablesthe correct engine speed to be main-tained. Conversely, a larger-pitch pro-peller is more suitable for a smaller oper-ating load.Yamaha dealers stock a range of pro-pellers, and can advise you and install apropeller on your outboard that is bestsuited to your application.NOTE:At full throttle and under a maximumboat load, the engine’s rpm should bewithin the upper half of the full throttleoperating range, as listed in “SPECIFICA-TIONS” on page 4-1. Select a propellerwhich fulfills this requirement.If operating under conditions which allowthe engine’s rpm to rise above the maxi-mum recommended range (such as lightboat loads), reduce the throttle setting tomaintain the rpm in the proper operatingrange.60201610-3/4x17-F1 2 300060112-1/4 x 9 - Gw eq