Cyclone Onan Generator - A few Generated fuel ?'s

I recently purchased a new 2018 3513 with the Onan 5.5. Since all of my outings have come with hookups so far, I haven't needed to run the generator. Does anyone know the generator fuel tank size/capacity? Also, has anyone found a simple method for checking the fuel level in the generator tank? Finally, what fuel octane is best?

Hi iamspecialized,

Welcome to the Heartland Owners Forum. We've got a lot of active Cyclone owners, so I'm sure you'll get some answers shortly.

iamspecialized said:

I recently purchased a new 2018 3513 with the Onan 5.5. Since all of my outings have come with hookups so far, I haven't needed to run the generator. Does anyone know the generator fuel tank size/capacity? Also, has anyone found a simple method for checking the fuel level in the generator tank? Finally, what fuel octane is best?

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How many fuel tanks does your Cyclone have? 2 ? If so, it should be the front tank for the genny, which you’d have to fill from the nozzle connected to the rear tank. The tanks are not interconnected.

Regular gasoline is all that is needed. You should consider a fuel stabilizer - ethanol treatmnet additive as well.

Don’t you have a fuel gauge inside near the remote gen start switch?

porthole said:

How many fuel tanks does your Cyclone have? 2 ? If so, it should be the front tank for the genny, which you’d have to fill from the nozzle connected to the rear tank. The tanks are not interconnected.

Regular gasoline is all that is needed. You should consider a fuel stabilizer - ethanol treatmnet additive as well.

Don’t you have a fuel gauge inside near the remote gen start switch?

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Thanks for your response. I do have two tanks. From what the dealer explained, the forward tank is for the gen, and the rear is the fuel station for the toys. He also said the gauge light on the inside control panel is for the fuel station, not the gen tank. Is that not accurate?

iamspecialized said:

Thanks for your response. I do have two tanks. From what the dealer explained, the forward tank is for the gen, and the rear is the fuel station for the toys. He also said the gauge light on the inside control panel is for the fuel station, not the gen tank. Is that not accurate?

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Welcome and congratulations on the Cyclone

Front tank is for generator, rear tank is the auxiliary and you can manually pump from it into the front tank with the fuel station pump when you get low, there should be a fuel pump timer in the control panel as well. The fuel gauge in my 3800 control panel has a rocker switch, one way to view generator tank level, the other way to view the aux tank level, as far as sizes of the tanks I’m pretty sure they are 20 (gen) and 30 (aux). I use 87 octane and Sta-bil fuel stabilizer every time.

On our Cyclone, the front tank for the generator is 20 gallons. The rear tank for the fuel station is 30 gallons. Regular unleaded fuel is all you need. Our gauge in the control panel has a rocker switch - push it one way for the fuel level of the generator tank, and the other way for the level of the rear tank. And generators like to be used, so we fire ours up at least once every couple of weeks whether we need it or not and run it for awhile to keep in good condition.

jmarnell said:

On our Cyclone, the front tank for the generator is 20 gallons. The rear tank for the fuel station is 30 gallons. Regular unleaded fuel is all you need. Our gauge in the control panel has a rocker switch - push it one way for the fuel level of the generator tank, and the other way for the level of the rear tank. And generators like to be used, so we fire ours up at least once every couple of weeks whether we need it or not and run it for awhile to keep in good condition.

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Oh yea, don’t forget to run it periodically to “exercise” it, let it warm up for 5 minutes then put a load on it, they don’t recommend running them unloaded. If you didn’t get a manual here’s a link, this has all of the maintenance intervals and part numbers for filters, etc. you’ll also want to get a good fitting oil filter socket, I can’t remember the size but it finicky.

https://power.cummins.com/sites/default/files/literature/rv/F-1123-EN.pdf

New cyclone and Always on shore power so generator will not be used often. I hate to have gas go bad which can happen even with additives so I’d like to keep tank empty as I don’t have any toys.

Whats involved with converting gen to lp?

other ideas?

emery395 said:

New cyclone and Always on shore power so generator will not be used often. I hate to have gas go bad which can happen even with additives so I’d like to keep tank empty as I don’t have any toys.

Whats involved with converting gen to lp?

other ideas?

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I would personally put 10 gallons in the gen tank with Stabil or Seafoam additive and run your generator once a month loaded for at least an hour.

I run no other high draw items except for 2 ACs plus 1 heater on 1000 watts after the generator warms up. With these 3 large draw items and no other 120V items that can kick in unexpectedly (resi fridge or hot water heater)...my draw is 41 amps.

Your 5500 is rated at 45 amps, so that is a good hefty load. The fuel line sump in the gen tank does not go completely to the bottom of tank, so a few last gallons of gas shouldn't be drawn up.

10 gallons would let you run the generator for a few months....not enough time for the gas to go bad.

Also, non ethanol gas only should be used in gent and toys. Otherwise carbs will gum up and rubber parts will dry and crack. Puregas.org tells who has non ethanol fuel nearby. Good sit with free app