Yamaha 2 stroke high volts

[Murdo]

Hi, looking for some guidance to assist my own troubleshooting:

Was out for a few hours yesterday and noticed the voltage reading (from Garmin GPS) considerably high - up to 17volts at 5000 rpm.

Once at idle, dropped back to circa 13 volts. Did a hand test on battery and no obvious hot spots (access is limited though). All electrics ok thankfully.

Just going to check battery connections clean ants tight and put voltmeter across terminals to see if it’s the battery. (I figure get the easy stuff done early).

What else could it be - will check all bullet connections under the outboard hood too but if all tight. What next - new rectifier needed?

Forgot to add - Yamaha 75 CETOL 2009 autolube.

Thanks in advance for any steers.

[matata]

Have you got Yam instruments? Our Yam tacho is multifunction and it gives volts. Ive noticed that the yam voltage and the garmin chart plotter voltage we have differ by 0.5 volts...the garmin reading too high. Your voltage does sound high though???

[Murdo]

Hi. No, my gauge isn’t a Yamaha and doesn’t show volts but trust the garmin to be close enough I guess. I’ve got a new rectifier now, will install and see how it goes. Thanks for reply.

[matata]

Yeh, i reckon the rectifier is on the way out...Keep us posted

[Murdo]

Got it out for a run today with new rectifier on. Still showing 15.6 at 4000 rpm so I’m assuming that up at higher rpm would climb up again. Switch on lights and it came down to 13.5ish

Not sure now if I should just get a new battery in case there’s something wrong with that. Any advice gratefully received.