Question about Merc stators...?

[Bartman39]

Have a Merc stator that we thought was a 40 amp but here is the problem... The old stator has 4 yellow wires that go to the dual regs but the good used unit I have only has 2 yellow wires and have eye terminals on them...? Is this a 40 amp or is it a 16 amp stator and can you use the 16 amp with the 40 amp flywheel and a single reg of course...? Is`nt this the trick setup some of you use on your fishing motors...?

thanks just want to be sure of what I have...?

[sosmerc]

That is the old 40 amp stator that was used in conjunction with the large water-cooled regulator that mounted into the water jacket under the coil mounting plate. 1989 vintage I believe.

[Bartman39]

Ok I can go with that but can I hook it to 2 of the newer style regs (using a jumper setup) and use it like that or do I have to have the old type single reg and figure out how to cool it...? (Just wonder if the values are the same, meaning volt wise...?)

Also I assume it will work with my electrical parts like the switch boxes and ECU...?

[Dave S]

Thing to do is get the rite part. You have the not rite part.

[Bartman39]

Thank you and I understand that but not the answer(s) I was asking...
Just want the technical approach to this and see if it can be done... I was an aircraft electrican in the USAF several years ago and learned sometimes you cant always have the right part when you want it but there is always a way around things... If it comes down to it I could just build my own reg it not like something impossible to do...

[sosmerc]

The 40 AMP stator you have MUST be used with the older style regulator.
I believe the best approach would be to purchase a newer 4 Wire 40 AMP stator to use with your dual regulators.
You might want to call CDI/Rapair Electronics to discuss with them the possibility of a modification to your old stator...but I still don't think that's the best way to go...especially if you have an EFI engine.

[j_martin]

The water cooled regulator runs one 40 amp circuit. It was very troublesome, is very expensive to replace, and requires water to keep it cool. There is even a plumbing mod on engines that used it to keep it cool.

To divide one 40 amp coil among 2 20 amp regulators that are not limiting by design, but rely on stator magnetics to limit the current, would require resistors, and you'd then have the trouble of getting rid of hundreds of watts of heat from the resistors. I guess you could do it with a mosfet switcher, but then you might as well design the rest of the power supply. Open circuit voltage on the stator coils is around 100 volts.

You could re-invent the wheel, but why bother when you can find a dual coil 40 amp stator on eBay for under a hundred bucks.

The "trick" setup for fishing motors is to route one of the 2 20 amp regulators on a dual regulator system to the trolling motor battery. Gives it a kick when you fire up the main motor. Helps get through a tough windy day when you'd normally run out of trolling juice, and greatly lessens the probability of accidentally killing your cranking battery with a crossover switch and missing the check in.

hope it helps
John