Output voltage

[Ndheep]

I have an 82 40hp mercury thunderbolt that left me stranded last Sunday. Was running than died and wouldn’t restart. Battery was low. After I got towed home and put the charger on it got it going again. voltage didn’t change after it was running. So I ordered a rectifier. Got the rectifier put on and the voltage goes up a little from 12.4 to like 12.6 or so. What voltage should I be getting.

 

[dingbat]

I have an 82 40hp mercury thunderbolt that left me stranded last Sunday. Was running than died and wouldn’t restart. Battery was low. After I got towed home and put the charger on it got it going again. voltage didn’t change after it was running. So I ordered a rectifier. Got the rectifier put on and the voltage goes up a little from 12.4 to like 12.6 or so. What voltage should I be getting.

I would bet an ice cream sandwich that your battery needs replaced.

Batteries typically don't fair well after being run "low"

What is battery voltage one hour after removing it from the charger?

When was the last time the battery was load tested?

 

[dubs283]

Perform the proper stator/rectifier tests for static state

Replace the battery with a known good one

Run the motor and perform stator output test

 

[Ndheep]

Boat is new to me. The battery started the motor after it sat for a week off the charger. While at idle I’m getting 4.5 volts on either of the two posts on the rectifier and 12.5v on the output post. I will test the stator tomorrow with it unhooked and see what I get. When I went to get the boat he had to jump start it. Leaning to the stator

 

[dingbat]

While at idle I’m getting 4.5 volts on either of the two posts on the rectifier and 12.5v on the output post.

You do realize the input (two posts) are AC and the output is DC?

Outboards don't generate charge current below 1,500 rpm or so

 

[Ndheep]

Yes I measured the input in ac. I will test farther tomorrow when I have time. Good to know it won't charge at low rpm. This is my first boat and first outboard I'm working on.

 

[Ndheep]

So stator and rectifier work as they should. Thanks for the help.

 

[Ndheep]

Put new battery in it and turns out the starter is not engaging. Took the starter out and cleaned it up works better but I'm going to order a new one. And replace the cables while I'm at it.