Mercury 15" 1500 inline 6 Battery Ignition system & Charge system specs

[scott reierson]

Need some help from the Inline 6 guys on a 1973 inline 6 150hp with the Big Coil Battery ignition/Charging system.

Does anyone remember/know the specs on:

1973-1975 Mercury 150-hp inline 6 Stator Voltage and amperage output once it comes out of the DC rectifier to charge the battery? at Idle RPM. Mid-Range and lets say 5000-6000

What does the battery ignition system draw for amperage at idle RPM. Mid-Range and lets say 5000-6000 12-13.5 volts?? (5, 10, 15 amps)? .

I do have a 1975 owners manual that recommends a 100 amp hours battery which seems huge.

I am calculating the reserve time I have with my current battery setup based on engine only running draws. I need to double check my meter readings against the factory specs.
This system is not regulated so its pumping some amount of juice all the time. I need to confirm the battery has enough room to take it.

Thanks, Scott 608 347 0027

[Capt.Insane-o]

The stator is 9 amps at idle it might make 3. I've idled around for hours with no problems.

I think you sent me a pm right before Greg did the forum upgrades and a few disappeared over the course of that

[scott reierson]

Thanks for the reply back. That info really helps.

Yes I believe I did send you a PM. Then I saw it was gone.

I've been pondering a new setup for my Vector that I wanted to run by you and the battery setup i'm using. I'll send you a PM again.

[Dave S]

It has been soooo long.....but I think there were 2 diff stators/ flw…….bigger dia...… just don't rembr……...you are best to get a good battery......as the old dist motors will fart out burn pack w/ low volt...….I love the 1% and then it sparks...a 12 volt exciter coil /capatator…...of that ingintion system...…..slow crankin speed? Zapp….Usta pull my Mk 78 creation.... if it didn't start on 3hrid pull.... bring me back to the beach.....Sorry.... don't know how it works..

[scott reierson]

Thanks Dave...I thinks I got a handle on it now. My meter will not measure this primary systems amperage flow as its to low for my meter to read.

After 40+ years of V4, V6 Mercs and OMC's... I now know more now about my 150 inline 6 Mercs than I ever expected to. Thanks to all of you guys for the education. I appreciate it.

The motor starts and runs fine. I was just curious as to what amperage the ignition system needs to run. I did test fuse the red primary 12 Volts at the box & then the key switch a 10 amp fuse with no issues.

Part of my reasoning to look into this, was when I installed a replacement CDI cowl harness plug and saw how little those wires are compared to the rotted factory size wire.

It amazes me that this ignition system can function with so little juice in the primary before it crosses over the secondary to get to that spark level. Amazing what a switch box and coil can do with so little input.

With the proper care and adjustments...The fact that these old boxes, coil and distributor still perform so well after all these years amazes me. The Crankshaft reed system blows my mind and the fact there is no cylinder head you can take off! Wow!