Older Yamaha Outboard - Identification, Alternator & Battery Connection

[boatvinnie]

Hi,

A couple of questions, would appreciate a reply.

Just got a 16' pontoon with an older Yamaha 20HP motor (my first boat - it's a start). It is in bad condition, but was cheap and runs well. Function over form and all that.

The motor serial plate reads:
Yamaha 20 CM
6A9 L 300252

Looking this up at http://www.yamaha-motor.co.uk/products/marine/outboards/model_codes.jsp yields that it is 20HP, 'C' generation, manual start. However can anyone identify the approx year it was built? Are 20HP Yamahas uncommon?

Also, does anyone know how powerful the alternator is on this?
I was hoping to run it to a battery and power a small marine/car stereo and some lights off it, will this be sufficient?
The battery will not be used for starting, and the stereo etc will almost always be used when the motor is running.

The 2 charging wires are currently cut off right next to the motor. Do I just run wires from the motor straight to a battery or do I need something in between? Is there any way I can test the output first? What readings should I get using a multimeter at idle? Under full power?

Once a battery is connected, can I just run the stereo/lights straight off the battery? Or do I need something else in between?

Any recommendations on the size or type of battery that would be needed?

Much appreciated.

 

[gazzarose]

Re: Older Yamaha Outboard - Identification, Alternator & Battery Connection

Sorry for dragging up an old post, but did you ever get anywhere with the charging system on your engine? I've got the same engine on one of our little ribs, and weve just build a console for it complete with lights and fish finder, but only just thought about the engine sid, Im not sure if we need a reguator or not. Annoyingly I work in a yamaha dealer, but because its a '93 engine, its effectively out of living memory, even my boss cant remember what the score was back then, I may try yamaha tech support, but I dare say it might be told of to be of any interest to them.

Gareth