Yamaha C90 Rectifier/Regulator Test

[msmith1356]

So the other day, in a hurry, i hooked up the battery backwards. Bonehead move! Anyways, tracked down the 20A inline fuse, replaced it and everything 'seems' to work. It'll crank and the tilt works.

I have been reading that crossing the polarity on the battery will fry the rectifier in a heart beat. So my question is, how do i test if it works? I have read on a number of posts to check resistance between the different leads, then swap them...showing that current can only move one way. But when i do this, i seem to be getting different readings than anything i'm seeing online.

The unit has 4 wires coming from it, Red, Black, and 2 Green's. When i test between the Red and Greens or the Black and Greens, this works correct...current only travels in one direction. But when i test Red to Black, it works in both directions.

Does this mean it's fried?

 

[robert graham]

Re: Yamaha C90 Rectifier/Regulator Test

2 weeks ago in a mad rush to get to the lake I hooked the battery up backwards on my 90C and all it did was fry that 20Amp fuse under the cowl. Thank the lord for fuses to protect screw-ups like me! Everything else is working fine.

 

[99yam40]

Re: Yamaha C90 Rectifier/Regulator Test

Crank up the motor while voltmeter is attached to battery, if voltage comes up to 13.5- 14.5 volts it is functioning.

 

[msmith1356]

Re: Yamaha C90 Rectifier/Regulator Test

You're right...the voltage on the battery doesn't change. Damn! It hurts paying $115 for your own screw up.

Won't happen again!

 

[msmith1356]

Re: Yamaha C90 Rectifier/Regulator Test

Just to follow up on what i found...

I went down to my local marine repair and after talking with the guy for a while, he explained to me that the voltage wouldn't go up unless you crank the engine and increase the RPM's. He said especially for the 'C' series, they don't really increase the voltage until you get it rev'ed pretty high. So came back home, idled it high, which increased the voltage to just under 13v. Good for me!

Took it out the next day just to check the readings under full power and it kicked it up even higher (13.15v) which is exactly what the guy said it should read.

Thank God for fuses and cool mechanics!