Chief, how right you are...
...I've been working with a major equipment manufacturer that's been having problems with Honda GX670's on multiple units. They say they don't run right, run rich, won't idle, run only at half coke, things like that. Most have been "no problem found"s for me, but one did have a bad coil and shorted stop diode assy., so I replaced those under warranty and sent it back. I usually get these off the equipment. They called after the last one and said it still wouldn't run right after they re-installed it on the equipment. I had them send it over still on the equipment. Well, after checking comp. and leak, valve clearance, etc. and running the thing out back to confirm the symptom, I did agree that it was running a little rich. But later that night, at home, I kept smelling diesel on my shirt cuff. I don't work with diesel. All it could be, I reasoned, was that I had gotten gas on me, and the gas evaporated and left the diesel behind, which I smelled every time my hand came near my face. The next morning I took the thing out back again and detached the fuel line, ran it to empty the carb. bowl, and hooked up my own remote fuel source. BAM! Thing ran like a dream. No more hard starting. No more ease the choke gently open. No more white cloud of smoke when you throttle up from idle. Thing ran perfect. Just like a new engine should. I think this distributor has a problem with whatever fuel reservoir they have to work from, as this problem was not isolated to this one unit, but has been an ongoing problem in many units, all with Honda engines (maybe the Hondas are more sensitive than other manufacturers?). What would be ideal would be something with an eye-dropper that I could drop a couple drops into a sample of their fuel and it turns blue or whatever and I say, "See, you got diesel in your gas." Seems like such a product must be available somewhere. I'll keep my eyes and ears open.