2551 blowing 20 amp circuit

Looks like I need to invest in a power watchdog, whatever I end up doing.

Thanks to everyone for all your helpful replies. I'm sorry if I get answer each one but I got overwhelmed with all the responses. But rest assured all your responses with helpful and I'll use them.

Thanks, again.

OK here's what ended up happening with this problem. I realized my MH 30 amp extension cord that came with it plus the 30 amp one I use at home is long enough to use at my sister's. I also bought a 30 amp Hughes power watchdog, and one 30amp to 20amp converter and one 30 amp to 15 amp converter in case hers are actually only 15 amps. She's having all of her outdoor receptacles changed out since she said they were too old anyway.

I'm working on a back up generator and getting my in house one fixed. My experience has not been good with service places. It's like it costs 1k the second you pull in and then they don't even always fix the problem. I'm not laying that kind of money out for that loud ass Onan 4000. I'm going to find a local person I can trust to work on it. It's probably just a gummed up carburetor. God I hate 10% ethanol gas. I actually have bought another one to replace it but gashed my dominant hand open last week and it's not working right now, or probably for a while. (I's an impressive gash believe me.) I think I've troubleshot or replaced every other thing on the generator that could be causing the problem.

Thanks everyone so much for all your help.   

Hey, sorry about your hand.  That's rough. 

It looks like to me you have done everything that  might be causing your problem.   I thought of you earlier today when I pulled my PC in beside the house and plugged in to my 20 am outlet.  It was 97 degrees with a reasonable heat index of 101 but that is still pretty hot.  I have the AC going, the rig cooled down and the fridge of electric.   All is well.  Hope your problems resolve soon.

I agree with having something worked on because it is really hard to find someone competent to do the work.   We have an excellent independent rv service group locally but they don't work on Onan generators because the Cummings folks are a half mile down the street tfrom them.  We all know how that works out.  $$$$$$$$$$$$$$$$$$