If it runs on gas, the carb should be ok, your problem is with the propane part of the system. Have you checked your propane pressure being fed to the generator. You could have too much or too little pressure feeding from the regulator. At any rate, the regulator could be bad or the fuel selector switch could be bad.

I just had a similar issue with my Pulsar 12000w dual fuel generator. It was the valves needed to be adjusted. They were not far off just a thousandth of an inch, but it was hard to start and backfiring even more than yours.

Bought one like it so wnen I'm out of town my wife would be set with a generator, forget about it!!!! Hurricane came power out ⚡......brand new generator wouldn't start at all.....had to send it in for service....brand new......by the time the next hurricane was approaching in a few months it was still not ready.......they told me I could go pick it up unrepaired if I wanted 🤨.....I was not priority......

That is exactly what mine is doing. This piece of crap let me down right in the aftermath of two ✌️ different hurricanes......

I’ve not had any issues on propane, but have heard of issues w/the selector switch on the gas side which, DuroMax sent out a replacement. There’s a video on bypassing the gas selector switch!

I have the exact unit it’s one year old this month. Will always crank on gasoline but for some reason not on propane. Have been in contact with Duromax about the problem and when it described it had backfired during a startup on propane they decided I needed a carb and are currently trying to get one to me. In the meantime I’ve been watching some KZbin videos on this same problem with like Duromax generators and someone from Duromax had advised this person that that the spark plug that comes in the unit is the problem. They have advised him to replace it with a NKG iridium plug BPR6EIX and sent him a carburetor to replace the one this is damaged by the back firing. Seems the little plastic choke gears on top of carb are being stripped when the backfire occurs due to less than quality spark plug installed from Duromax ! Generator ran flawlessly after replacing both but would backfire again when he installed the original plug. Get a new spark plug and carburetor and problem solved. Plastic gears on choke are Not quality either 🤬 hope they get and upgrade

Torch plug is 99% of the problem with it 😮😢😢😊

First you need a 20/20 box fan blowing on it😮

Too much combined pressure intake? My understanding the choke is only for gasoline mode perhaps this is for specific make / model

Good idea

Had to do the same thing. Fuel type selector switch went bad back when Ida hit.

Having the same problem with mine when I first got it. Backfired several times on propane just as yours does. I warmed it up on gas and switched to propane and it ran good. I have added a natural gas regulator to mine which will run on both natural gas and propane, it starts and runs great now. You can share this video with Duromax and hope they can advise you as to what to do. Mine also had the same surge as yours and I reached down and held the choke open and the surge went away. Choke open is all the to the left. There are KZbin videos out there the show you how to covert natural gas and what parts you’ll need. Mine runs great since I converted it. You will be able to use natural gas and propane through the same regulator.

I know this part was on back order but there is a video to show how to disable the fuel choice switch which is pretty simple until the part arrives

It appears you never shut the gas line off to the carburetor

F= frequency yes herz. Not sure why its low but honestly, it will really only affect clocks driven by the frequency and motors will run a little slower. Lived in europe many years using transformers for 110 appliances they use 50 hz. If you haven't already change spark plug to NGK Bpr6es. Nice work though.

For those with this problem, swith out the spark plug to NGK Bpr6es this is recommended by duromax support and solves this type of problem.

I read somewhere when using propane to open the tank valve slowly. Open too quickly, the regulator safety will restrict the gas flow.

I have the same model. It ran good for a first 4 days, then the multimeter stopped working and then carbon monoxide detector light came on, machine got shut off and never be able to start back up. It’s sad to buy this generator as a back up in case of emergency, but unable to use it when you need it the most

The CO2 sensor might be going off if there's a intake leak (carburetor to engine) the vacuum cleaner test will indicate that kind of leak. Gasoline engines are vacuum pumps so checking for vacuum leaks is always a good idea.

In my experience as a mechanic normally backfires are caused by exhaust leaks. Its really easy to check, allow the engine to cool down but really cool down. Using a shop vac, tape the vacuum hose to the exhaust muffler outlet so it doesn't leak than turn on the vacuum cleaner and you will be able to hear vacuum leaks. Do this with engine off and it's ok to hear your throttle plate have a whistle sound. This can also be done on automobiles for backfiring iss and O2 sensor code issues.

Need bigger tank problems solved

Never run on gasoline carburetor will go bad

In my manual from Duromax they say you should not use any propane tank smaller than 40 lbs. The tank you are using is not 40lbs.

Did you switch to a NGK spark plug? The spark that comes with it is a POS.

Well brother you just showed us how to convert from gas to propane while this thing runs. I too have had issues with propane. At least we know now you proved you can swap to propane while it's running. Good to know and thank you. I just bought this and had the same issues with starting on propane. Serious backfires and RPM up and down until it quits on LP. Gas seems to work fine but this dual fuel system has issues at start up using propane. Hope it powers my hut. Guess I'll see here soon when I test this thing I just bought.

Cheap propane regulator

Need to test propane gas pressure at the unit..... That length rubber hose and regulator on tank doesn't look current...... Depends on the electrical load and engine RPM...... Lower gas pressure will cause backfire and shutdown.

I was in Washington State, about 2 months ago, it was raining and when it stopped I saw a double rainbow it was so close to where I was I could run my hand through it, it was the most amazing thing I've experienced.

they have invaded!

Iconic i would say

Who yall are?

Why yt recommend this 😅

You may be wondering why I've gathered you all here today.

It's been 10 months since you put video, have you resolved the issue? I have 2 simple solutions to fix your issues.

This video feels like a lost ancient internet artifact

What is this?

I'm just as confused as you are.

Y it have so many views 😂

why was this recommended

why was this recommended to me

tf

Check spark plug gap should be at 0.30” or 30 mils. Also reminded that I change the regulator to a adjustable regulator. Pressure should be between three and five psi.

Where do you get 100lb propane tanks on the cheap...and how do you get them filled?

These Duramax generators have a serious design flaw. The selector switch is used to run propane or motor Gasoline can be defective. What I did for a friend of mine, was to bypass the propane and bypass the motor gasoline. One thing to remember is, if you were going to run the generator on propane, the selector switch must be over to the propane position. There are wires connected to the switch, and the switch needs to be activated. The NGK spark plug should be gapped at 30 mills. I think the selector switch works, and then it stops, and then it starts working again. Hence bypassing it is an easy thing to do and eliminates the switch issue.

Oh, imagine sitting in a tiny Kei car like this and a Karen in her F150 is breaking up with her boyfriend on the phone. 😱 @9:16 There is a lot to love about those care. The newest iteration is the Honda N-Box. ☺

See James Condon. 😊

It's the automatic choke

I have the same gen. Same problem as your's. I changed plug, regulator changed the secondary regulatir. Didnt help. I think the problem is with the automatic choke. Watch it sweep back and fourth during startup. It backfires when the choke is fully closed.

Northstar with Honda engine.

get a magnet!