HG and OC3 magneto questions

My magneto in my Oliver HG keeps crapping out. Takes 2-3 hours of hard use with my HG crawler before it starts losing spark and finally dies. Once it cools off, it works fine again for a few hours. It's been doing this for years but now I am moving it to a very remote location and want it working right. My little HG is a user, not just a collector's item. Has a six-way blade and an aux. trans and is a great little machine for trail work.

Has the Hercules IXB3 engine and has had a mag from an Allis Chalmers on it since I owned it (30 years). Fairbanks Morse FMJ4BA3. I'm pretty sure it has a bad coil. I'd like to get a replacement mag and put it on. Then fix the old one and keep it for back-up.

The most common mag I see for sale is a new Wico XH1113. I also see a few places selling the Wico XH894.

One thing I am wondering. There are brand new military surplus mags for sale made by Slick to go on Continental four-cylinder engines. I am wondering if such a mag would work? Only $100 brand new, old stock. Flange-mount, CW rotation, 5/16" drive-lugs, and 15 degree impulse. My Hercules calls for 20 degrees but I assume it might work anyway? This is a Slick model 56 magneto. Anybody ever tried one? $100 seems like a bargain.

Two things will generally affect a magneto like that. Capacitor or transformer windings. Could be either. Modern contact points would be burned if the capacitor is poor, but old originals may not. I would suspect the windings are shot. Spares are not hard to come by, especially as it is an important workhorse.

I know the capacitor is not the problem. When the problem first showed up years ago, I tested the cap (it was good) but replaced it anyway. Nothing left to go bad except the coil. As far as spares go - not as common as I thought they'd be. I'd been watching classified ads and Ebay for years. Wanted to find an original Wico to rebuild but none have come up. Yes, I can buy a new one for $400 plus. Just something I've been hesitant to do. I am still trying to figure out if the brand-new Slick magnetos can be made to work. Slick Aviation made them for the military to be used on F-162 Continental gas engines. $100 each is a good deal for a brand new mag. It has the correct rotation and mount. Only issue I see so far is the impulse. Mag is made so the impulse only works when mounted sideways. So I am going to take it apart and see if I can changed it so the impulse dogs catch when it is mounted vertically on my Cletrac.

I'd have to see, but I believe I have a couple of those mags for parts. I know I have pieces for one off an HG, but I don't know what I have left, and I did have one off a Farmall AV that had a broken spring, I believe it is still kicking around at the other farm somewhere. If you need parts, let me know, I'll give em to you if I can find them.

Ross