56Maintenance Instructions CHECKING/SERVICINGIMPORTANT: DO NOT overfill the battery. Electro-lyte will overflow through the vented caps onto partsof the machine and WILL result in severe corrosion.Cleaning the TerminalsIf battery terminals are corroded, remove batteryfrom the mower. Using a wire brush, remove corro-sion with a solution of one part baking soda andfour parts water. Rinse with clean water. Coat theterminals with petroleum jelly or terminal protectorspray to retard further corrosion.Charging the BatteryCheck the battery charge by measuring the specificgravity of electrolyte; if specific gravity is less than1.225, the battery will need to be charged as follows:1. Charge the battery at 15 amps for 10 minutes.DO NOT exceed 20 amps maximum recom-mended charging rate. Charge until specificgravity is at least 1.250. Total charging timeshould not exceed one (1) hour.2. After charging the battery, use drinking water toadjust the electrolyte level to the bottom of thevent wells [1/4 to 1/2 in. (6 to 13 mm) above theplates].Tire PressureInflate tires to pressures shown below:Deck Caster Wheel = 20 PSI (137 kPa)Drive = 15 PSI (103 kPa)Rear = 20 PSI (137 kPa)Sharpen Mower BladesCheck mower blade(s) for straightness, sharp-ness, condition of the cutting edge, and balanceevery 10 hours of operation (or more often whenmowing abrasive type grass or operating on sandysoils). Replace blades if worn, bent, cracked, orotherwise damaged (refer to REPLACING/RE-PAIRING the Mower Blades in this section). Use thefollowing procedure to check and sharpen blades:NOTE: Keep blades sharp - cutting with dullblades not only yields a poor mowing job but slowsthe cutting speed of the mower and causes extrawear on the engine and blade drive by pulling hard.1. Stop the engine, remove ignition key, and dis-connect the spark plug wires before raising themower deck to service blades.2. Raise the deck and secure it in either the UP po-sition using the deck lift rod (non-tilt deck) or inthe TILT-UP position. Refer to CLEANING theGrass Buildup in Mower Housing in this sec-tion for deck raising instructions.3. Check the blades for straightness by markingthe blade tip position inside the deck housing,and then rotating the opposite end of the bladeto the same position and comparing. If the dif-ference in blade tip track is more than 1/8 in.(3 mm), the blade is bent and should be re-placed.DANGERBATTERIES PRODUCE EXPLOSIVEGASES• Charge the battery in a well-ventilatedarea, so that gases produced while charg-ing can dissipate.• Keep sparks, flames, and smoking ma-terials away from the battery at all times.• Make sure the battery cap vents are open(check manifold vent on each cap).• Make sure the battery charger is un-plugged before connecting or discon-necting cables to the battery.DANGERNEVER operate cutter blades with thedeck in the raised position.