Charging Issue

[Toulla]

Guys,
2001 F25 ELHZ. Ever since new, while running, the engines'regulator showed output of 14.2 Volts. About a month ago I installed a new battery, started the engine and again both the GPS and depth sounder showed 14.2 V. During my last outing I noticed the voltage output, according to the GPS and depth sounder displays was only 12.4 to 12.5 V. I am suspecting the regulator on the engine. Made it home ok and the next day I run the engine at the dock. The displays started out reading 13.9 volts and quickly dropped down to 12.5 V Need help on how to go about testing it. I do have a voltmeter but which wires to I probe? In the meantime since this happened after installing a new battery I am having it tested to eliminate ,it as the issue.

Thanks!

[99yam40]

If it is anything like my C40 2 stroke the manual says to measure the lighting coil out put with a peak reading voltmeter (Or DVA adapted with regular meter) with R/R hooked up and then without it hooked up if the voltage reads too low.

A Yamaha service manual for your motor is a very good thing to have if you plan on working on the motor yourself

[Toulla]

charging issue

Thank you! I will need to get the adapter for the voltmeter I have. Battery eliminated as the culprit. The engine has 560 hours of use if the regulator checks out ok what else should I look at and is RR failure a common occurrence on these motors?
Thanks.

[Toulla]

charging issue

Got the adapter tested the RR and confirmed it was bad. Visited my Local Yami dealer. $202.00 later all is well again.... Went to the dealer with my owners manual, which has the Serial number of the motor written in it and the bad RR. Still the parts counter person insisted that I had a Mercury. I said Yeah, mercury motor with Yamaha decals. I was given the crazy look. Anywho! I am back on the water and charging again.
Thanks for the comeback 99Yam40!

[almetelo]

Until a certain time Yamaha F25, F30 and F40 where made by Mercury
(I think the F25 is still done by mercury but not sure)

I'm rebuilding a Yamaha F40 and most mercury parts for that motor are much more cheaper.

If you can know what Mercury your Yami match always compare parts prices (thats what I would do)

[rodbolt17]

the marriage between mercury and Yamaha was ended in an FTC ruled divorce about 2003.
once the contracted motors were finished they parted ways by late 2004.
mercury marine sued Yamaha over an alleged dumping scheme.
at the time Yamaha made the mercury f115,f200 and F225.
about 2003 mercury was trying to market their verado line of 4 strokes.
merc lost the lawsuit and the companies parted ways.

but in the case of an 01 f25,about the only difference between the merc and the Yamaha was the engine harnesss connector and the paint color.