Yamaha 90a Owner's Manual

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Contents

Yamaha 90a Owner's Manual Manual pdf 34 page image

28InstallationEMU26902InstallationThe information presented in this section isintended as reference only. It is not possibleto provide complete instructions for everypossible boat and motor combination. Propermounting depends in part on experience andthe specific boat and motor combination.WARNINGEWM01590● Overpowering a boat could cause se-vere instability. Do not install an out-board motor with more horsepowerthan the maximum rating on the capac-ity plate of the boat. If the boat does nothave a capacity plate, consult the boatmanufacturer.● Improper mounting of the outboard mo-tor could result in hazardous condi-tions such as poor handling, loss ofcontrol, or fire hazards. For permanent-ly mounted models, your dealer or oth-er person experienced in proper riggingshould mount the motor.EMU33470Mounting the outboard motorThe outboard motor should be mounted sothat the boat is well balanced. Otherwise, theboat could be hard to steer. For single-en-gine boats, mount the outboard motor on thecenterline (keel line) of the boat.EMU26933Mounting height (boat bottom)The mounting height of your outboard motoraffects its efficiency and reliability. If it ismounted too high, propeller ventilation mayoccur, which will reduce propulsion due toexcessive propeller slip, and the water in-takes for the cooling system may not get ad-equate water supply, which can causeengine overheating. If the engine is mountedtoo low, water resistance (drag) will increase,thereby reducing engine efficiency and per-formance.Most commonly, outboard motor should bemounted so that the anti-cavitation plate is inalignment with the bottom of the boat. Theoptimum mounting height of the outboardmotor is affected by the boat/motor combina-tion and the desired use. Test runs at differ-ent heights can help determine the optimummounting height. Consult your Yamaha deal-er or boat manufacturer for further informa-tion on determining the proper mountingheight.1. Center line (keel line)ZMU017601