just as a note, out of 4 generators that i rebuilt last year, thats 12 injectors total.....i had every one gone through by storeman and there wasnt a single one that was in spec. they were all out. even if they are clean you cant expect a spring that has been compressed for 30 years to still be holding the same psi as it should. if its off just a little then engine power will suffer. you could have one sticking or popping at a low or very high psi and not atomizing properly. not saying this is your problem but it never hurts to remove your injectors and have them tuned. its easy to do and inexpensive. if it turns out not to be the cause then you are out very little and you have narrowed your search.
I agree entirely.
I'm having a similar issue with mine. My thread is long gone but i won my auction for my '93 002a with 89 hrs on it in april. Went thru the entire machines fuel delivery system from top to bottom. Got it running easily. Built a load testing station , and put everything aside for another project. Now summer is nearing its end so i pulled out the generator this past saturday to start it up and put a load on it to see how it did. I put a hair dryer and a dual bulb halogen work light on the machine for a total of 2200 watts and it bogged down from 62 hz to 55 hz immediately. Upon reading this thread sunday night, i removed the blower cover for good access to the star adjuster on the governor. I found the spring was at its top most position on the star screw adjuster. I have since moved it down to dead center but havent tested the machine yet as i have 2 other household projects i'll be wrapping up shortly. I hope this resolves my droop issue.
On a lighter note, i also sent my injectors off to storeman for a rebuild. If i remember correctly, neither were off more than 1000 psi from spec. I think one was only off by like 200 psi. Storeman may chime in if he remembers. But my machine only had 89 hours on it so we didnt expect the injectors to be off by much.
Regardless, in my opinion its very very smart to get the injectods out of the machine, out of the heat sinks, adjusted properly by storeman, and reinstalled with liberall amounts of antiseize between the injector and aluminum heat sink. I now have the security of knowing that part of my whole ststem has been gone thru completely.
Good luck with your issue. If tou dont mind , i'll post my results later this week as well. I love this site !