ok, there are a few different kinds of Mags. One the type you guys are getting into, Hunt and Vertex donot carry external "transformers", not coils. The MSD and Mallory do use transformers. The MSD Promag has had two transformers available, one was the regular box and the other is the "endurance" box. Msd has dropped the regular box and only offers the endurance box, designed to be run for longer intervals. They say they over heat after a while, I'[ve known people to run a Vertex in there boat and not be able to touch it after a while. I run an MSD now w/ transformer and revlimmiter. I was running a Sprintmag I, whick I might add has been in the boat since it was new, '82. I changed Mags because I got the MSD ($1345) for $150, not counting the box, cap & rotor, wires and hold down. I when I got the boat it had been sitting for about 6 yrs the told me. When I got into it at home, no spark. I went all thru the internet including Zigs to find someone to go thru it, After all the I looked at the mag, had a sticker on it that said, "point gap .016". So I cleaned the points and set 'em at .016 and BOOOYA, spark been runnin eversince. I learned thru all that that some old mags have magnets that need to be recharged....like every season, must most mags around today have the "rare earth" magnets and dont need to be recharged. A few other things a guy should know if running a mag is, NO resister wires or plugs and gap the plugs at .018-.020. Also a good heavy duty ground switch is needed, this is the only control you have on the mag, you ground 'em to kill 'em. These things make more juice the faster you turn 'em but at startup, 250 RPMs minimum, you barely got juice so close the plug gap down a little to get the candle lit. Remember NO resistance in plugs and wires it requires the mag to produce more zap ansd overheats them. Hope theat helps and if anyone has any questions....fell free.
