Specifications and requirements11your Yamaha dealer.The remote control unit must be equippedwith a start-in-gear protection device(s). Thisdevice prevents the engine from starting un-less it is in neutral.EMU25694Battery requirementsEMU25721Battery specificationsThe engine cannot be started if battery volt-age is too low.EMU36290Mounting batteryMount the battery holder securely in a dry,well-ventilated, vibration-free location in theboat. WARNING! Do not put flammableitems, or loose heavy or metal objects inthe same compartment as the battery.Fire, explosion or sparks could result.[EWM01820]EMU36300Multiple batteriesTo connect multiple batteries, such as formultiple engine configurations or for an ac-cessory battery, consult your Yamaha dealerabout battery selection and correct wiring.EMU25730Without a rectifier or RectifierRegulatorNOTICEECM01090A battery cannot be connected to modelsthat do not have a rectifier or RectifierRegulator.If you wish to use a battery with the modelswithout a rectifier or Rectifier Regulator, in-stall an optional Rectifier Regulator.Using a maintenance-free battery with theabove models can shorten the life of the bat-tery significantly.Install an optional Rectifier Regulator or useaccessories rated to withstand 18 volts orhigher with the above models. Consult yourYamaha dealer for details on installing anoptional Rectifier Regulator.EMU34192Propeller selectionNext to selecting an outboard, choosing theright propeller is one of the most importantpurchasing decisions a boater can make.The type, size, and design of your propellerhave a direct impact on acceleration, topspeed, fuel economy, and even engine life.Yamaha designs and manufactures propel-lers for every Yamaha outboard motor andevery application.Your outboard motor came with a Yamahapropeller chosen to perform well over arange of applications, but there may be useswhere a different propeller would be moreappropriate.Your Yamaha dealer can help you select theright propeller for your boating needs. Selecta propeller that will allow the engine to reachthe middle or upper half of the operatingrange at full throttle with the maximum boat-load. Generally, chose a larger pitch propel-ler for a smaller operating load and a smallerpitch propeller for a heavier load. If you carryloads that vary widely, chose the propellerthat lets the engine run in the proper rangefor your maximum load but remember thatyou may need to reduce your throttle settingto stay within the recommended enginespeed range when carrying lighter loads.For instructions on propeller removal and in-stallation, see page 59.Minimum cold cranking amps (CCA/EN):20DWO 347.0 AMinimum rated capacity (20HR/IEC):20DWO 40.0 Ah