Convert Onan 4000 gas generator to propane

[j carter]

Has anyone converted their Onan 4000 gasoline generator to propane? Propane burns cleaner, and would not reduce gas mileage.
What are resources for conversion kits?
Is a conversion difficult?
Is a conversion costly?
Is a conversion reliable?
Thanks,
Jim Carter

[NewBlackDak]

It will take 1.36 Gallons of propane to create the same power you would from 1 gallon of propane. A 20lb propane tank holds 4.7 gallons.

The few friends I have with newer units with propane generators aren’t really happy with them. Sounds easier, but when you need it(dry camping) the fridge, hot water heater, cooking, and possibly the furnace are eating propane too. 5 gallon gas cans are much easier to carry than spare propane tanks.

[D Gardiner]

My stepdad did the propane conversion on our Onan 5000 Marquis 10 years ago. Honestly can state the generator starts easier, and the carburetor never needs cleaning. A bonus for us.

You may want to try these people.
Change over any Onan engine to run on propane or natural gas.

[followingsea]

Originally Posted by NewBlackDak

It will take 1.36 Gallons of propane to create the same power you would from 1 gallon of propane. A 20lb propane tank holds 4.7 gallons.

The few friends I have with newer units with propane generators aren’t really happy with them. Sounds easier, but when you need it(dry camping) the fridge, hot water heater, cooking, and possibly the furnace are eating propane too. 5 gallon gas cans are much easier to carry than spare propane tanks.

Propane is the limiting factor when boondocking in my MH with a 30 gallon tank feeding my LP Onan. So when a plan a longer stay, I use a small gasoline generator to charge batteries.

[Libero]

Jim

I don't have any experience in converting a generator from gasoline to propane on any of the many RVs (motorhomes) I have owned. Something I would never do. In fact I would not want to run my generator on anything that was not the same as the fuel that powered my motorhome. Why is this? Primarily it is because of the availability of fuel. You can get gasoline & diesel at almost any corner - but not so for propane.

Just 2 cents worth from an old codger with nearly 60 years of RVing experience. Yes next month I will be an octegenarian and still RVing.

Good luck with the conversion - IMHO - it may reduce the resale value of your unit.

[Goodspike]

Originally Posted by NewBlackDak

It will take 1.36 Gallons of propane to create the same power you would from 1 gallon of propane. A 20lb propane tank holds 4.7 gallons.

The few friends I have with newer units with propane generators aren’t really happy with them. Sounds easier, but when you need it(dry camping) the fridge, hot water heater, cooking, and possibly the furnace are eating propane too. 5 gallon gas cans are much easier to carry than spare propane tanks.

The power difference can translate into the generator producing less power (fewer watts). That would depend on engine sizing. But when you're looking at portable generators they generally produce less power on propane than on gas or natural gas.

As to the fuel, I would argue propane is easier. Carrying around spare gas cans makes me nervous. Also, propane never goes bad.

Conversion probably isn't difficult, but the system I have on my portable clearly won't work because you need to manually prime when starting.

[RVPioneer]

Couldn’t it be converted to run on propane while still being able to run on gasoline as well?

I converted a portable Yamaha 3K to propane that still runs on gasoline.
Dual fuel.
Options.

[j carter]

Originally Posted by RVPioneer

Couldn’t it be converted to run on propane while still being able to run on gasoline as well?

I converted a portable Yamaha 3K to propane that still runs on gasoline.
Dual fuel.
Options.

Very good question about dual fuel capability.

JC

[Goodspike]

Originally Posted by j carter

Very good question about dual fuel capability.

JC

I don't know about dual/tri-fuel generators installed in motorhomes, but you would need something to select the fuel. So that might be more difficult. It's not like selecting electric or LP on a water heater, where that selection selects the fuel. When you're starting a generator you're causing the engine to suck in fuel, so you'd need something to tell it what fuel to suck in.

But in general, dual and tri-fuel generators have a device in-between the carb and the engine that supplies the propane or NG fuel. It's probably possible with a built in generator, I'm just not familiar with such a device, and am pretty sure it's different than what I am familiar with.

[RVPioneer]

Originally Posted by Goodspike

I don't know about dual/tri-fuel generators installed in motorhomes, but you would need something to select the fuel. So that might be more difficult. It's not like selecting electric or LP on a water heater, where that selection selects the fuel. When you're starting a generator you're causing the engine to suck in fuel, so you'd need something to tell it what fuel to suck in.

But in general, dual and tri-fuel generators have a device in-between the carb and the engine that supplies the propane or NG fuel. It's probably possible with a built in generator, I'm just not familiar with such a device, and am pretty sure it's different than what I am familiar with.

On my converted, portable Yamaha, all that is required to run on propane is to shut off the fuel/gas, connect a propane tank and open the propane valve. The valve on the tank acts as a shut off for the propane. All that would be required would be a shut off for both fuel sources. Easy enough. It would take a bit of manual labor to select the desired fuel prior to starting the generator.

[Goodspike]

Originally Posted by RVPioneer

On my converted, portable Yamaha, all that is required to run on propane is to shut off the fuel/gas, connect a propane tank and open the propane valve. The valve on the tank acts as a shut off for the propane. All that would be required would be a shut off for both fuel sources. Easy enough. It would take a bit of manual labor to select the desired fuel prior to starting the generator.

It sounds like you may have one of the snorkel type devices. Mine has a diaphragm that shuts off flow when the engine stops, but I always disconnect too, not trusting it. I believe the Champion I was considering also uses a snorkel type device because the instructions to turn off are to shut off the gas.