Generator's RPM Woes

I'm going to go through this, really just in the hopes that someone knows how I can handle it better. I held the back-up back-up generator in reserve even though it's newer and has an electric starter, because it has engine governor problems I was never able to diagnose. I kludged it together in a way I'll describe below.

Several months ago, when it was the principle back-up generator, its engine overheated and stuck a valve. This is fairly common with B&S 2-stroke engines, and I fixed it at home with no more investment than a new head gasket. I had no reason to believe there was going to be any problem, since I've repaired dozens of engines in the same way. But this time, when I started it after the valve job, the engine firewalled. I mean it screamed. Nothing, but nothing I did to it should have caused this, and the only reason it didn't come apart was because I was standing right there and could lunge at the off switch. Poking around, I determined that, for whatever reason, the mechanical governor was no longer working. So we loaded the whole thing into the truck and took it to the shop where I worked at the time.

To get to the governor, you have to take the whole freaking thing apart. I did so, and couldn't see a thing wrong with it. My boss, a master with these engines, couldn't see a thing wrong with it. There was simply nothing wrong with it ... except that it didn't work. I put it all back together again, started the engine, and of course it screamed. Well, now I had a problem. I had already given my notice at the shop, and my time there was coming to a close. Taking it apart again, in addition to being pointless, was not possible - at least not at the shop. We tried everything we could think of, and finally we punted.

There's a spring that's supposed to pull the throttle wide open, which the governor fights against. That way when there's a load on the engine, the governor can back off and bump up the RPM to compensate. If the governor isn't working, of course that spring yanks the throttle wide open and holds it there. No good. So we reversed matters: We installed a spring that held the throttle closed, and extended the idle stop until the idle speed was high enough that the genset could produce 120 volts at 60 cycles. The problem with this, of course, is that when the controller demands more current it puts a load on the genset, which slows down the engine RPM, which causes the output electrical to drop below useful levels. So you can idle the engine too hot, which will give you enough juice under load, or you can idle it safely which will give you not enough power. Ew.

I've had nothing but trouble with this thing since the Coleman locked up. As I feared, I erred so much on the side of engine safety that it's almost useless as a generator. So today I snipped a loop off the idle stop screw's tension spring and bumped the engine speed up to where I'm making a little more than 125 volts with no load. The engine is running faster than I like, but hopefully not dangerously fast. I connected the generator to the electrical system, and the system seems happier now. But needless to say, I'm not real happy. Does anyone with more knowledge than me have any suggestions?