How perfectly should my Onan run?

Chum lee wrote:
I don't mean to be a smart *ss but are you having any problems running equipment with the genny? Any problems starting it, reaching maximum output, excess fuel/oil consumption, exhaust smoke, overheating, noise, spark plug fouling, etc? I have the same unit and I can't hear yours, but, mine does change speeds/voltage slightly depending on load, altitude, temperature, etc. It has never failed to do what I ask it to do. Years ago I learned not to try to fix problems I don't have and I spend my time resolving the ones I do. Could you be expecting too much? Just asking. You have a very popular genny. It might be worthwhile to listen to others and see what they sound like before you condemn yours.

Chum lee

I don't think this is a smart*ss point at all! It's really why I'm here: The thing runs, never pops down below 57 hz for more than a half second, and powers my A/C and microwave well enough; I'm curious if this is just how it's gonna be or if I should keep pushing it.

re: other comments, let me read it back to you guys:

• Two main suspects: Poor carburetion or poor governor springs.
  
• If it's the carburetor, I'll likely need to replace it, given that the interventions so far haven't yet fixed it (I tried carb cleaner and air, then a very Berrymans-heavy external gas tank over several days, then an ultrasonic bath). If I really wanted to, I could poke around in the carb with strands of small-gauge copper wire, but even that wouldn't guarantee anything.
• If it's the springs, I can replace them and redo the governor calibration, and I should see improvement.

I'm gonna do the following:

• Drop by the Cummins guys tomorrow and pick up the two governor springs (the main spring, short and fat, and the spring parallel to the throttle linkage, long and narrow) in addition to an air filter (worth a shot). Install same. I'm a little wary about how much of a pain it's gonna be to replace that main governor spring by reaching back into the genset from the access panel, still mounted under the rig. Any advice there?
  
• Redo governor calibration by: adjusting speed screw at idle to 62-64hz, checking that pulling throttle tang against stop screw drops hertz to steady ~55hz and genset doesn't die, applying heavy load and observing hunting pattern, adjusting sensitivity screw counter-clockwise by one or two turns to decrease sensitivity to eliminate any hunting condition, re-adjusting speed screw in light of new sensitivity screw position, lather rinse repeat until I observe a drop to 58-60hz under load with no hunting condition.
  
• And if none of that works I'm either gonna close the access panel and live with it, or I'm gonna put a new carburetor in it.

Quick edit: I'm also going to check the choke linkage and housing and starting-temperature setting. Possible something's wonky there, considering bad behavior on startup that subsequently evens out considerably after the unit (and thus the exhaust-heated thermostatic choke) has heated up.