1990 150hp XR4 voltage regulator problem.

[leftone]

I need to replace the regulator (oem# 18736-a13) on this motor. Mercury shows it as NLA (no longer available.
The 18736-a13 has 7 wires out of it, 2 10ga yellows, 2 10ga reds, 1 16ga red, 1 16ga gray, 1 16ga blue.
I found a used 18736-a15 but it only has 6 wires on it, it's missing the 16ga red wire that mine has.
Can this regulator be used with a little re-wiring? How?
Thanks

 

[Laddies]

Re: 1990 150hp XR4 voltage regulator problem.

Goto the CDI site or call them and they will explain what to do.

 

[j_martin]

Re: 1990 150hp XR4 voltage regulator problem.

That must be a 40 amp water cooled regulator. Where does the 16g red wire go? It's not in my XR4 40 amp diagram.

Generally, yellow goes to stator, Red goes to battery, grey goes to tach, and purple (blue to you, must be color blind) goes to ignition.

The water cooled ones aren't available any more. Your options are
1. Get the one you have your eye on, and put it in. (I'm sure the extra red wire is not needed, but a jumper may be needed somewhere)
2. Change the stator to a dual regulator stator. To do it properly involves mounts and stuff.

hope it helps
John

 

[Texasmark]

Re: 1990 150hp XR4 voltage regulator problem.

Agree on seeking professional advice, but the small red probably operates the electronics in the engine. The heavy red would go to the starter solenoid (input side) and the other one back to the battery to recharge it. They are all tied to the same point inside the regulator for convenience.

You could follow the small red wire to see where it attaches. Then if you have enough wire, just cut off the existing wire at the old regulator, lug it with a lug to fit the terminal on the starting solenoid where one of the large red wires attaches and you are there. No biggie.

If the wire is too short, auto parts stores have wire and terminals, make your own jumper....heat shrink tubing over the crimp will help to maintain joint integrity.

Mark