You said ONAN 4000. Is the model number "4KY?" If so, I summarized carb removal above. You need to flex the blower housing a little. That's what the Torx T-30 screws are about. Then there's only 2 bolts, 1-mm hex heads, holding the carb and they're accessed after the air filter is off. No need to drop a 4KY to remove the carburetor.
If Model is NOT 4KY, then what is it, please...
I sprayed some WD-40 on the joints (3 years ago) when it wouldn't retract and have not had a problem since.
I had the same experience. There's a group who remind us how WD40 isn't a lubricant and how it dissipates quickly, but I sprayed our step mechanism like Linda did and it's been fine since. Probably been as long, too. There's a joint at the motor that looks like a ball and socket. But ours was making a creaking sound so spraying it was a good guess.
BY ALL MEANS be careful around the steps and linkage!!!
Yeah, our Ford Class C had dual tanks. Electric pump in each tank, feed and return line each tank. So.. the Tank Select Valve switched between the two pairs of lines representing two tanks, onto one feed and one return up to the carburetor. Yep, the carburetor, no mechanical pump on the engine. Same valve also had contacts to switch which pump ran and which tank sent levels to the gas gauge. The select valves are still available, aftermarket, about $100.
Back to this tread: On the link OP posted that shows the Relay's Location, scroll down a ways and there's a schematic of how the pump and relay are wired. That was where I decided a BOSCH/TYCO relay would work.
j-d: what year are you needing relay for?
For nothing. For MEX - nada.
I'm just trying to follow what OP is working on.
And it sounds like OP found a suitable relay. For his in-tank, mechanical-pump-feeding electric pump. Which seems to involve a relay and some kind of regulator.
But if he hasn't or what shows up isn't the right one, I'd say re-wire and use a BOSCH (TYCO). A 5-terminal one...
I hit the clicky "Fuel cut-off relay" on your 24AUG post and it took me to a relay on O'Reilly. Then I put my ZIP in and chose a store for "Price and Availability." At that point it said no nearby store had one and price was $120.99. I didn't look at anything earlier for EFI, at least didn't try to.
Glad to know the name change from BOSCH to TYCO. I pulled the relay pic up from Amazon, and they also have BOSCH Brand Relays, about $10.
Your mechanic experienced pretty much what I did working on the Jayco. The lines were drooping, they were deteriorated, and it was BARELY possible to reach the tank without dropping. And yes, it fills more easily than it used to. I try to park nose-down at the pumps if I can, but level works. I doubt if I could fill it nose-up.
What's Make/Model of this A/C?
Is it Ducted (like a central home unit, ducts in ceiling, wall thermostat)?
Or Non-Ducted (blows air only from the unit itself, controls are a switch knob and a thermostat knob)?
Can you SAFELY get up on the roof to do an inspection?
DISCONNECT POWER FIRST
Take the plastic cover and some of the internal sheet metal off?
Take and post a couple pictures?
Yes, it's possible to add a service port, evacuate, re-charge, etc. Usually doesn't work well because of labor cost, trying to find/fix the leak, difficulty of getting the EXACT right charge in it.
Used to use R-22 but have changed as of late.
If it's a Coleman, label on front left side of the sheet metal should tell you.
It uses at least two capacitors.
One is Fan Run, and apparently Fan and Cap are OK since it's moving air.
Other is Compressor Run. Could easily be bad if compressor isn't running.
The two capacitors could be in a common (dual) unit.
MIGHT have a Start Assist Capacitor also.
For Compressor to run, the Run Cap and the Start Assist both have to be good.
If you don't have a Start Assist, the Run Cap must be good.
Run Cap(s) usually metal cases. Start usually plastic case.
Pix we'd like to see: Label/Wiring Diagram, AND Capacitors.
See what you can do and report back.
MEX, funny you mention Tioga Pass. We went to Yosemite driving a Subaru Forester. Albeit from the West. We passed an old Lazy Daze on Chevy chassis on the way up. Then pulled over to take a picture and here came the Lazy Daze. Engine actually sounded like it was chugging Little-Engine-That-Could-Style. We found it on the side of the road with the hood open, after stopping at the ranger station. I'm guessing it either starved or vapor locked.
And why I don't recommend the Chevy/350/5.7 in a full Class C. They really struggle on a climb, and this one wasn't pulling a toad or trailer.
Yo! Bud! I was sure glad to be sitting when I clicked on the O'Reilly link and saw $120!!!
Believe I'd be getting a Bosch Relay and Socket
Just have to be a little careful. There seem to be "Bosch" Relays with only 4 contacts, meaning no "back" contact closing an alternative circuit when the relay is NOT energized. OK to use only 4 pins of a 5-pin relay so long as the back contact isn't needed. OP's diagram says it IS needed.
We found where some of the later Workhorse Class A chassis used a "Siemens Relay" that does the same thing but in a different form factor. Carried GM part numbers.
Would still like to know more about the "regulator."
In 2002, we have the tail-end of the 4R100 generation. Ford took the venerable C6, a three-speed, added an overdrive that engaged electrically, and called it E4OD. Then in 1997 they added an all-electronic control system (solenoid-operated valve body) and called it 4R100.
C6 was a bulletproof icon. E4OD had lots of failures, at least at first. 4R100 seems to have been good.* Same for 5R110/TorqShift. Very surprised the low-mileage one had a problem. 'Specially Phil's - he seems to take care of things.
*At least behind gas engines. The annoying downshift they do on slight grades take it from 4th-locked to 3rd-locked. That annoyance means the torque converter doesn't run around unlocked. Behind diesels they apparently do, and overheat. This is from a credible third party source. I didn't dig it out myself...
I think I've got the gist of this. The 454 has a carburetor fed by an engine-mounted mechanical fuel pump. BUT SOME P-30 models have an in-tank electric pump feeding the mechanical pump. OK so far? The electric pump is powered through a relay. The relay powers the pump IF either, driver is cranking the engine, OR the engine is running, determined by oil pressure.
OP believes the in-tank pump isn't running due to a bad relay or not staying running due to an intermittent relay.
A likely scenario, but... Are all filters new or clean, including the little one in the inlet of the Quadrajet? And, is the mechanical pump good?
I bought a BFA used, same complete Model and Spec as yours, and soon realized the fuel pump was in trouble. I remember tinkering with it and replaced with a "Mr. Gasket" type from the local auto supply. It was actually a Purolator, which is now Facet-Purolator. Store had "low" and "high" pressure versions of the pumps and the "low" fit into the pressure range specified by ONAN. I failed to realize that ONAN wants a pump that serves as a shutoff (gas can't be pulled or pushed through) when not running. The Purolator model I bought turned out to not be of that type, but it was never an issue.
The Parts Manual shows the Pump as I remembered it, with the twist-off cap at the top. I have a set of manuals for BFA so PM me with your email and I can scan some pages for you. Let me know if/what you need.
Our carburetor was varnished up, and I couldn't clean it up with repeated attempts. Luckily there was "still" a carburetor rebuilder willing to do other than automotive. It ran better after that but the RPM still "hunted." Replaced the Governor Spring and that solved it. Best couple dollars I ever spent on a project! Service manual lists the Spring several steps down in the troubleshooting for "hunting" but wife suggested I just get one instead of tearing the governor apart and what all else. That BFA is a genuine Power Plant, not the glorified mower engine the newer ones are.
Rectangular but rounded relay, contacts in a row? Or more like a cube, four contacts arranged like a Capital "E"?
Either way, if this works, you're that quintessential Happy Camper.
Let us know how you do...
New baseplate and ordinary coach-mounted tow bar around 14-1500. Half or less used. Then a braking system. 200 or more used to who-knows new. Ready Brute Tow Bar combines a nice aluminum bar WITH a braking system. Definitely an option to look at. Then Plus Labor... Or Not, if you can install. Install instructions by specific models is available for most of this stuff.
Remove and replace is not all that difficult.
First, STUDY the LINKAGE carefully and Document How it Goes with CLOSEUP Photos. Then...
One or two T-30 screws have to come out, then air filter off. Disconnect fuel line and electrical connector. Two long 10mm screws through Filter, Blower Housing, Gasket, Carb, Gasket.
Then put the air filter wingnut on upside down. Use that as a purchase to pry the filter base and blower housing far enough away from the carb to clear the choke and throttle plates. Disconnect Choke and Throttle/Governor Linkage. You've got it in your hand.
Looking at Home Depot, they show a 4-ft Werner-brand ladder
that's like my Husky. Even green, so I'm thinking there's some private labeling going on here.
The step-up from our cockpit floor to the house floor is 8" and the ladder just fits. Catches the edge of the bunk but nothing sticking up above it.
Do you think you'll want to expand the bunk every time you go to use it, or leave it in "bed mode?" The first C we had, we left it in bed mode and had to, as we'd stuffed a residential queen mattress up there. Made getting between cockpit and house a little difficult, but we had 5' clearance and were not climbing up an 8" or more ledge either.
The ladder we tried first in the older Class C (5-ft climb) was a "Skinny Mini" that looks a lot like the Cosco versions.
Quality product but not very successful in the cabover bunk application. Nice wide steps but it has to be opened to use, and that made for an extra pair of legs to find a footing for.
You can see both Costo and Skinny Mini on Amazon. A whole lot easier than crawling through the Home Depot web maze.
I got the 5-ft aluminum step ladder I mentioned before from Ace Hardware. The Big Box stores seem to have 4-ft and 6-ft but not 5-ft. I paid more for 5-ft at Ace than 6-ft at Big Box. Walmart probably has them.