Honda BF8, BF9.9 and BF10 Outboard Motors Shop Manual., Page 403Get this manual
SELECTION Selection of the optimum propeller in regards to boat characteristics and outboard motor performance is of utmost importanceTo ensure smooth acceleration, top speed, smooth handling and good fuel economy select propeller which is designed for your boat size and outboard motor outputConfirm that the boat reaches its top speed at full throttle and in the maximum engine speed
TOP SPEED CANNOT BE REACHED AT FULL THROlTLE
In this case the propeller is not properly matchedLower the propeller pitch by one size (I- inches), to avoid power loss and potential outboard motor damageIf it is necessary to lower the engine speed, select propeller with pitch one size largerIf the following cases occurl acceleration will improve and the life expectancy of the outboard motor will increase by lowering the propeller pitch- At heavy loads (Crew, load, equipmentl water skiing, etcin places with high temperatures and high humidity,when using in higher elevationswhen the boat bottom needs cleaningwhen the area around the gear case is obstructed, andwhen there is propeller damage