Troubleshooting A Firman Generator That Starts But Won't Stay Running  

Question:

Helpful Expert Reply:

Have you tried checking the fuel filter and fuel lines on your Firman 10,000-Watt Portable Generator # 333-P08003? A clogged fuel filter could let just enough gas fuel in to start but then not enough to maintain. I also recommend unplugging any loads you have on the generator before trying to start it. A leak might not always immediately show so I would inspect the fuel lines to see if maybe there's some dry rot. They also recommend checking the air cleaner (part number 114 in the parts diagram) and seeing if it needs to be cleaned or replaced.

If the issue still persists then I recommend reaching out to Firman directly to see if they might have alternative troubleshooting list to check.

expert reply by: Kevin C

1

333-P08003 Troubleshooting
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John L.

3/16/2026

Ours doesn’t have 1 hour on it and it won’t stay running. Fresh gas, it dies under load and no load. Did we just get screwed out of a Grand!?!?

Kate F.

3/16/2026

@JohnL Hi John, Sorry you’re having trouble with the generator. If it starts but won’t stay running with or without a load, even with fresh gas, there are a few simple things I would check first. Make sure the oil level is full and the generator is sitting level. These Firman units have a low oil shutdown and if the oil is a little low or the generator is tilted it can start and then shut off shortly after. Also check that the fuel cap vent is turned on. If the vent is closed it will start but stall once fuel flow slows down. After starting, the choke should be moved to the run position once the engine warms up. Leaving it on choke too long can cause it to stall. It’s also worth confirming the fuel shutoff valve is fully open and that the spark plug wire is firmly connected. It is also important to make sure that you do not have too much oil as it can cause it to foam which will result in the oil level sensor to shut it off as well. They have a 3 year warranty, when did you get yours?

John M.

3/21/2026

Kate F. Thank you very much for your reply! Good info was included. Here is a new problem for you. It works great on regular gas, as long as we have a fan put in front of it. Even though it’s in the open with plenty of airflow. We tried propane, it won’t run at all!!!! Ideas??

Kate F.

3/23/2026

@JohnM Since it won’t stay running on gas even with no load, and won’t run at all on propane, this points more toward a fuel or air issue rather than setup. On the gas side, starting and then dying can mean the carburetor isn’t getting consistent fuel. This can happen if there’s a partial restriction or a bit of debris, even on a new unit. On the propane side, no operation at all usually points to the regulator not allowing proper flow. I recommend resetting it by turning the tank off, disconnecting and reconnecting the hose, then reopening the valve slowly. Opening it too quickly can trip the safety and restrict flow. If you haven’t already, trying a second propane tank is also a good idea, just to rule that out. Let me know how that goes. I know you said you only have an hour on it, when and where did you purchase it? I don't see an order under your email, need to know in case I need to reach out to manufacturer if this doesn't fix it.

John M.

3/23/2026

Kate F, all great ideas and I’ll get on it as soon as I can. Thank you so very much for your help! God bless you, and I’ll let you know how it works out.

Kate F.

3/23/2026

@JohnM Yes, please do! God bless you as well John =)

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