Troubleshooting an Onan Marquis Gold 5500 Generator - Part 2 

You see that t looking thing to the bottom right of the dip stick? That is the drain for the oil. Spin that and it comes out a hose at the bottom. No need for a shampoo pump

I was thinking the same as Ray, along with a few other checks. I will be trouble shooting mine today. Starts for 15-30 seconds and shuts off. at times the top 30 amp breaker release too. I will check the fuel pump, fuel filter, circuit breakers, wiring, the auto transfer wires and connections (should always check those periodically regardless, how many fires start), and if need be the wires and connections inside the coach breaker. the coach runs fine on shore power, so that should narrow it down to the generator connections or gas flow. I cleaned the carb, and the plugs are pretty much new. I will keep everyone posted. Please share what your findings where should you have had a similar issue with your generator... Thanks!

Maybe this might help others...mine was a drive belt failure. If engine doesn't detect output voltage from generator then engine shuts down. Try starting generator while looking at generator to see if spinning. No spin then faulty belt.

What was the problem

What ended up being the issue?

Great Video what did u find out mine does the same

Please post what the shop did to get your gen running?

he said in another video that it was the air intake manifold, i wonder if he could have changed that himself. looks like just a couple bolts????

THIS IS HOW I FIXED MINE, IN THE CASE OF.... "I CAN'T START MY GENERATOR" It's has been two years since last time it was running, so I started by checking oil level full at gen dipstick (it won't start if low oil because of sensors) then I checked gasoline more than 1\4 tank in the RV (also safety sensors), sparkplug checked for good spark, also checked the manual reset circuit braker ( to be ON) at front motorhome engine compartment for 12v current to the generator to be able to start it, also cleaned the carburetor and even installed new one but same situation, then checked wires and found some has been chewed like gum by rats at the back of starting switch generator panel so I replaced them, at this time the generator started but stay running only by keep pushing the switch on all the time, so then finally I knew it was internal electrical problem from the engine itself, so I took the generator out from my RV to work in my garage, (I did this by myself with some tools and old Mayan tricks ) lol, it's really heavy for one person. I disassemble the unit at my garage and started by removing the cover, then the cooling fan or flywheel unit (it's 2 items in one) until finally I was at the gen rotor and brushes assembly area and this is what I found: one more wire chewed by filthy rats plus the stinky rat nest in the middle of the generator motor coil, I fixed the wire and sanded the commutator copper contacts where the brushes are sitting becouse they were real duty with old urine from the rats, and of course I got rid off the stinky nest, lol!!! Then I assembled everything back together and... bingo it's runing like a champion!!! For this project materials involved was about $60.00 including an aftermarket new carburetor and an harmonic balancer/steering wheel puller (available at any auto parts for $25.00) to pull the aluminum fan out and (flywheel). Just picture this: (Any gasoline engine run smooth if gasoline and DC current aren't interrupted) so following this important principle you'll always find the problem to be fixed. Also if you have a onan microlite 4000 like mine, don't run it for more than a minute without the cover because you'll cook the engine real fast, also keep the eye on the aluminium fan and your fingers after cranking it in case you missing one or two members...just kidding, lol!!! After testing the gen then I did put the air cooling assembly back and the rest of components including the cover, now it's ready to be installed at my RV. Once the gen was installed back at my motorhome I started it to be tested for electric power but not before flipping the electric switch (on) at the gen starting control panel (sometimes hiding under or around the panel) to transfer power to my RV GFCI main outlet and electric panel as well, my motorhome it's equipped with GFCI so I reset it and tested for green led light indicating power is ready at my main breakers panel, so I turned my main breaker (on) along the others ones but no power was present at my breaker main switch (faulty main braker) so I flipped it many times, sometimes you can make it work again, mine did work, lol!!! I'm happy because everything works now including the ref for cold drinks and AC for this crazy summer, lol! Later I'll buy me a new main braker, for now this is a resurrected generator story that needed to be shared. If this can help eaven one person to save time and $$$ it'll make me more happy, thanks for reading!

This guy has absolutely no idea wtf he's doing. Do not watch this video. The error code TELLS YOU WHAT THE PROBLEM IS AND HE NEVER ADDRESSES IT.

Is probably the altitude adjustment

No, you have to ground the oil pressure switch wire to bypass it.

Adjust the engine speed/ AC frequency . Its the spring from the carb to the governor.

pinch the fuel line with a pair of vise grips

circuit board?

It’s got to be all for Mark and it will run

Why won't fuel come out of the bowl? I'm having the same issue.

first thing what I would have done: disconnect the fuel line at the carburetor to see if there is any fuel coming out of it when priming or cranking. Could also be the fuel pump.

You probably won’t see this but what if I removed the oil pressure switch power and it still turned on?

Consider using a vise grip pliers on the gas line to restrict the gas when pulling from fuel filter beneath the carriage.

I was wondering the same thing. What was the issue. I I got the same issue going on right now. But I just be clean up the Carburetor didn't by new one and yet. But it was a good video thank you

How do you change the spark plug wires?

Mine runs but no power no one seems to make a video of that

It’s not producing DC, so when you release the starter it switches to internal generated power, so you need to use a volt meter to see if coil continues to get 12v when you release, it doesn’t, low oil switch or over temp switch are most likely, I’m betting oil switch, check logic on schematic and either open or short to ground to test, in an Oman RV Gen set I had a blown resister R1 ( a big power resister) so no DC , without DC no field or AC, and exact same symptoms. you probably fixed it by now. But you have spark and gas , as the engine runs while holding switch

Orang for carb

Sounds like fuel pump

“A turkey baser works better”

Can you share what the issue was, please?

This is a prime example of what's called easter egging. I realize what you have done was cheaper than having it diagnosed professionally for what you replaced. But basic troubleshooting starts with testing fuel supply, compression and spark. You did none of these just throwing parts at it!

A carburetor will cost you 30 some dollars online and it will be sent to you no more than 40 bucks your governor is not working right

Loving the oil sucker...