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Mercury 650 -68 not charging battery

J

jhnlfgrn

New member
Hi!
I have an old Mercury 650 from -68 that runs ok but there are two problems:

1. It doesn’t charge the battery.:
I have read that it probably is the rectifier, but I want to check the stator first. I have two yellow wires to the rectifier from the stator. I have read that I can disconnect them and measure the AC between them when the motor is running. Is this the correct method? What voltage should I expect?

2. The motor doesn’t stop when turning the key off. When I measure the resistance between ground and the orange wire when the key is off, I get the reading around 400kohm. Shouldn’t that be much lower? Maybe it is a bad connection in the key switch?!
I am planning to install (at least temporary) a kill switch. Is it correct method to ground the orange wire that connects to the "blue" connection on the "switch box"? Se the picture.

/Johan
 

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Why not check the rectifier firstrectifier-testingsmall.jpg
the stator can be voltage tested while running; you should see 14+ volts at above idle.
 
Great with a manual for testing the rectifier. Thanks.
And is it correct that I should disconnect the yellow wires when measuring the stator?
 
jhnlfgrn said:
Great with a manual for testing the rectifier. Thanks.
And is it correct that I should disconnect the yellow wires when measuring the stator?
Click to expand...
Yes you can also use an ohmmeter to measure the resistance of the stator it should be around 1 ohm this is approx. [Without motor running]
 
Quicksilver said:
Yes you can also use an ohmmeter to measure the resistance of the stator it should be around 1 ohm this is approx. [Without motor running]
Click to expand...
Hi again.
The stator gives 1 ohm and open circuit when measuring to ground. That seems correct?!

I have also tested the rectifier. I get readings around 230 ohm in the "forward" position and open circuit in the reverse. The open circuit is correct but is 230 ohm in the correct range? I found a selenium rectifier testing guide and it said that 400-800 ohm is the correct range.
 
I have tested the stator while runiing the motor. At idle it gives out 5-6V AC and at 3000-4000 rpm around 14-16 V AC.
What do we say about that?
 
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