OK... on these ONAN gensets, various operational tests are bypassed when starting. as in holding the switch to START. Larger gensets have oil pumps, and oil pressure, oil level sensors were bypassed till you released the switch to RUN.
Don't hold me to this, but I think 4KY (28KV probably similar) won't keep running if it isn't producing electricity. They have less oil-related safeties since they're splash-lubed, but I'm pretty sure it has to be producing AC, and possibly also a 12VDC output to recharge the coach battery that starts it.
Is the genset far enough away from anything that's a fire or explosion risk? If so, try jumping the starter motor direct to 12VDC. Since the 2800 has a logic board, I think I'd disconnect the 12VDC "Hot" side from the rest of the generator for the start attempt.
Gas fumes or spills are obvious risks, but so is a Battery. Work too close to one and sparks can cause an explosion from battery gases.
THANKS for posting Model and Spec. Many don't.
This Link is for up to Spec "D" but might be of some help to you.
OH, as you check power and wiring, never neglect the GROUND. All too often we spend our troubleshooting on only the HOT side of the circuit.
I couldn't find a manual at the go-to site BryantRV.com, Chris has posted service manuals up to 86x but no 87's.
I can offer that fridges (water heaters, furnaces too) with a Logic Board want a certain minimum DC voltage to operate. You said your fridge IS sparking, but I still wonder if your battery, since your RV isn't plugged in, is up to a charge level that's considered adequate by the fridge's board.
What is the Model Year of the Frontier you're interested in? An OP here was interested in a 2017-something and I could get only the 2016 owner manual on line. Was that you?
I wanted a Tacoma (till I drove it, more later...) and ruled it out based on the owner manual prohibition. Next up was Ranger (they were still building them) and the ride was punishing. Then Frontier... Best ride, best price, towing allowed per owner manual. It drives well, has been very reliable, and we've found it very quiet. More like a midsize car than a truck. Minor gripe, front doors open so far it's hard to reach the handle from the seat when they're open to the wide detent. Bigger gripe, very large turning circle.
I wanted a base model but with extended cab. In Frontier, that's standard. Anyhow, at least in 2009, the Tacoma simply under delivered.
The truck that over delivered in a couple interesting ways was Ranger. Yes, ride was sub par, but steering was tight, small radius, and the engine had a spunky feel. Frontier seemed average, and Tacoma seemed lazy.
I tow a 2WD 2009 4-cyl 5-speed and another OP here just got a 2016 V6 6-speed, don't know if his is 2WD or 4x4. The 4x4, manual transmission, is to be towed with the Transfer Case in 2WD High Range. That essentially makes the 4x4 a 2WD. Then the manual transmission is placed in Neutral for being towed. The Frontier transfer case doesn't have a Neutral position, so the Automatic 4x4 can't be towed such as many can.
With manual transmission, Nissan has no speed limit for towing, but would like the engine idled in neutral (clutch engaged) every few hundred miles.
It's an air-cooled, splash-lubed single-cylinder 3600-RPM engine. That adds up to "about like a rotary lawnmower." Splash means no oil pump and that means no oil filter. Keep good oil in it, check it often, change it often, and you'll be fine.
Bookmarked this! We don't boondock or use a portable generator. STILL, many campgrounds we use are state parks with marginal power loops. Also, we have a 30-amp coach. It seems to me that one of these units would cut way down on tripped breakers and some of the "load shedding" we have to do on hot days.
The website offers the "board only" option which might be interesting to those of us who are tinkerers.
Kit, from what I've read over the course of years the 4KY carb is tricky to clean. We had a certified ONAN tech here who said some of the passages have right angle turns in them and difficult to impossible to clear out. Kinda like the first time I worked on a Toyota carburetor. Could barely get the wire from a twist tie in some passages. I think I plucked a piece out of a wire brush. The Pontiac we had, I think I could about use coat hanger!
Carb replacement makes sense too, if you could get parts but had to pay shop labor for the tinkering. With new, there's a far better chance the thing'll run right. We pay, but get happier the better and longer it runs.
Consider doing what some of us do - fuel stabilizer treatment every tank. I know that on ours, it was a matter of weeks (OK maybe 8 or so) after a new carb that the genny wouldn't start again. I fought it on and off a couple years before replacing the carb.
For anybody interested, changing carb on 4KY is pretty easy with a couple odd tools, a couple tricks, and a good picture of how the linkage goes.
You might want to try the Class C forum.
Even better, the Tech Issues Forum. If you agree, click "Notify Moderator" and request the move.
Also!!! Please include Model and Spec. Something like "4KY Spec J" but understand the Spec is important since it tells what features and mods the genset has. If you look up the manual, it'll say which Spec's it covers, and in the manual you'll see frequent references to Spec.
You ended up on the same path I took with an ONAN carb. I made several cleaning attempts and couldn't clear it up. Took it to a shop. You paid about half what I did, but I was as grateful as you are, and it took an ultrasonic cleaner to get it done. They called it a "rebuild" but that was years ago, when there were still some kits available. I could tell right away that the carb was better, but there was still a slight surge. Several steps down in the surge troubleshooting was "replace governor spring" and I decided to jump to that for $3 without all the other steps first. It did the trick.
GLAD you're enjoying a nice-running genny!
2500TS has wheelbase:length of 56%, decent for a Class C. Still, two of its three slides are behind the rear axle. Another few hundred pounds...?
Is the chassis a Ford E450? If so, I doubt the rear axle with its 9500 pound rating will actually be overloaded.
But still, if the wheelbase and rear overhang combine to make a light FRONT end, it won't handle well with extra weight hung farther out back.
You really need to weigh the coach! As loaded for travel, people and all. Ford expects to see 1/3 of loaded weight on the front axle. Many here use a bogey 75% of front axle capacity. That'd be 3750 pounds. Weigh it and come back.
So... I say we don't have enough facts to say you'll be happy with a scooter back there.
I can offer what IS fact however. The weight carrying rating of a hitch is based on an ordinary drawbar in its ordinary position in the hitch receiver. So a rating of xxx pounds means placed on a ball less than a foot from the hitch pin in the receiver. NOT on a lever a couple feet longer.
Only suggestion I have, look among shops that are tinkerers, that keep old parts hoping they can cannibalize them. Or a shop that replaces them with new. Again, carb "cores" that might be plugged up, but a few would have good floats. Those engines aren't only on gensets, at least I don't think so. Seen ONAN engines on welders, some small equipment, might be on marine gensets also.
Could it have been just a stuck fan?
Absolutely! It seems that your particular Rooftop A/C has separate motors for its Indoor (Evaporator "Cold") Coil and its Outdoor (Condenser "Hot") Coil. If it can't get rid of the heat that it's removed from Inside, then it'll overheat Outside.
Most of us think of an A/C that's more like their own than one that's different. The majority have a compressor and ONE motor up there. That one motor has a squirrel cage on the front end for Indoor Evaporator Blower and a blade on the back end for Outdoor Condenser Fan. So we would have ruled "fan motor not running" as a cause.
You should have access to at least one end of that motor shaft. Try some oil on it. Any kind but ideally not WD40 since it doesn't stay around long. I like "Turbine Oil" often called "Zoom Spout." Great for appliance motors!
HEY EVERYBODY!!! When you ask for help, be as specific as you can! Get Make/Model/Year or as much of it as you can. The generator gurus have about abandoned us because people say "my generator" when it's essential to a tech to have Model and Spec Code. Likewise for A/C... Make Model, Ducted or Non-Ducted, Wall Thermostat, which Kind. This is far more important than Brand of RV that it's in, until you get to matters of Chassis/Powertrain.
Persevere! Get it done and you'll be rewarded. Every trip, every pressure check, month after month. I adjusted pressure in early June and have only checked since. No air required before the trip we're on now. Call around, maybe you'll catch a shop on a slow day.
Live Long and Prosper!