I recently received a 2004 25 HP Johnson outboard with about 50 hours total time. After initially checking the battery (12.58 volts) and running the engine for about 10 minutes twice, I found the battery lost voltage down to 12.52 volts. Next, I checked the voltage at the battery while the engine was running about 1/3 throttle and found the voltage reading was 12.50 volts. It appears that the alternator is not having any output to keep the battery charged. I need a couple of things - any suggestions as to the source of the problem? - where do I find an online schematic showing wiring locations to check? - where do I find a mechanical layout showing where the alternator is? Thanks for your help.
