1993 Johnson Evinrude "ET" 60 degrees LV Service Manual, P/N 508286, Page 227Get this manual
Battery Specifications All batteries should be of heavy duty, marine constructionMaintenance-free or sealed batteries are acceptable for use ONLY with engines that are equipped with fully regulated charging systemRefer to Specifications, Section 1A deep-cycle battery must not be used as the engine's cranking batteryFor best performance, OMC recommends you use 12-volt battery with minimum rating of 500 cold cranking amps (CCA) at (105 amphrsat -18 C) and 99 minutes reserve capacity at 80 (2JO C)Battery Devices Battery IsolatorsIf you are rigging Loop "V" model where the engine's charging system will support two ormore batteries, you should only use one of the following battery isolator devices: One engine to two batteriesModel 2420 One engine to three batteriesModel 2424 Two engines to three batteriesModel 2423 The above battery isolators are manufactured by Guest ProductsBattery ON-OFF SwitchesIf you are using battery master on-off switch in the engine's 12-volt electrical system, be sure that the switch is equipped with "make-before-break" circuit to protect the engine's battery charging systemAvoid switching while the engine is running, and never turn the switch off unless the engine is stoppedBattery Testing