98 Mercury 40 Force not charging

[mercurymang]

I have a new battery. When at full throttle, I am not charging the battery. I have read as much as possbile but am somewhat stuck. I believe the problem to be my voltage regulator but it could be my stator. My stator has two yellow wires, and green/white and a white/green. Can anyone tell me how it's wired. I'm getting around 6 ohm across the two yellow wires so I suspect the stator is ok but want to be sure.
I tested the voltage regulator and checked the resistance from yellow to read and read to yellow and get the same reading which would indicate to me a problem.
Just hoping someone could help me with some information.

 

[Jiggz]

Re: 98 Mercury 40 Force not charging

The two yellow wires are the charging wires connected to the voltage rectifier/regulator. There is a gray wire which is for the tachometer. And then there is the red wire for connection to the starter solenoid which also connects to the positive terminal of the battery through a fuse and the ignition switch.

The best way to check if the regulator is working is to check voltage between the two yellow wires while the engine is idling. The voltage should be AC voltage around 25~30VAC. If there is voltage now it's time to read voltage between the red wire and to ground. The voltage reading should be in DC and it should be a little over your battery voltage. Write down the voltage .

Shut down the engine and now read the battery voltage from its terminal. If the voltage from the red wire and ground is higher than battery voltage the rectifier is working. The max output rating for the charging system is 9.0 amps which is roughly equivalent to 110 watts.

 

[mercurymang]

Re: 98 Mercury 40 Force not charging

Ok. I guess thats the first problem. I may have to go re-check but as I recall when I checked the voltage at the two yellow wires with the motor running, it was at around 2VAC which I thought was not right. I'm starting to think that both the stator and the vr are bad. What is the correct way to check the stator?

 

[mercurymang]

Re: 98 Mercury 40 Force not charging

Maybe you answered the question already. If i'm getting 2vac at the two yellow wires, is the stator bad.
Next question is what happens if I replace the stator and not the VR. Is it possible it could damage the stator?

 

[Jiggz]

Re: 98 Mercury 40 Force not charging

Re-verify your voltage reading first, with the yellow wires connected and also with at least one wire disconnected from the rectifier. Do not touch the wire use some kind of clips. With wires disconnected this will isolate if the problem is rectifier or stator related.

If the voltage is around 24VAC then the rectifier/regulator is bad. If the voltage do not come up to 24VAC try revving the engine to at least 1500 RPM and if the voltage is still not coming up to specs, then it's time to check the stator.

The charging coil of the stator (there are two ckts in the stator one for the charging system and one to power the CD modules) resistance is really low. So basically as long as there is continuity (0.15~0.20 ohms) it should be good unless it is grounded somewhere.

 

[mercurymang]

Re: 98 Mercury 40 Force not charging

Ok, i re-verified my stator voltage with one leg off of the VR. I also bought a new voltmeter. This test showed the voltage to be in spec around 35v at half throttle, 20 just above idle. So I moved on to my Voltage Regulator. I tested resistance between the red and each of the yellow wires both ways(polarity switched) and found i had very low resistance either way. This tells me that the VR is bad(shorted), correct?

 

[mercurymang]

Re: 98 Mercury 40 Force not charging

Just to wrap up this thread. I replaced the voltage regulator yesterday and everything seems to be working now. I'm getting 14v at full throttle. Interesting little note, my old VR had a ground wire (black) coming off of it and it was connected to ground via the bolt that secured the vr to the block. The new VR did not have a black wire so I made the assumption it grounded through the body of the vr. Also, the new vr had two red wires and the old one had only one. Looks like the PO may have done some rigging and I found a connector where it looked like he had spliced a connector in to split the two.

 

[Jiggz]

Re: 98 Mercury 40 Force not charging

I believe the two red wires off the regulator are one and the same. Although once connects directly to the starter solenoid while the other connects to the ignition switch, But it' all working now so you're good to go.