Re: Batery won't charge on my Yamaha 60 2 stroke!!
Hey lightning04 welcome to the fourm like me I am new to this fourm and I am also a seasoned Automotive Tech. ASE Certified in all Eight Areas, Master Tech. If you are familiar with OHMs law you can do all these checks but as Yam said before, a manual is helpfull.
Listen I had the same problem with my Evenrude 48, I suspected a stater and rectifier (regulater) there is a test that you can do but you need the book. If you have a rectifier, I realize you r working on a yamaha but look for an object. No better yet go to boatsdotnet (**********) and look up your engine model click on it and search the engine components specific to charging/stater/flywheel or somthing like that, it should be somewhere in that area, this will help you id that system or component.
I would also consider doing a voltage/charging test at the battery with a voltmeter conected to battery. Check voltage at idle and at a higher rpm sometimes you don't get a charging conditon unless you r over a certain rpm. This is true for certain size engines such as mine (Evenrude 48 SPL)
after that you might want to perform a voltage drop test starting at the starter and working back to the battery. This will eliminate any bad connections or wires. You should not have more than 3 milivolts drop through out the system. Do these test before you start spending money on parts u don't need, they can be expensive.
Again the book should tell you what wires to check on the rectifier and stator and tell you what the ohms should be seen on these parts. Another thing that I read is make sure you have a good battey and it is not internally shorted this can also cause a rectifier to go out and never disconnect the battery when the engine is running this can fry rectifier.
I hope this might have helpfull for you, good luck and hope you have your boat out in the water soon.