Propane question re dual fuel gens

[MountainGirl]

Does the propane pass through the same carb that the gasoline does? All my search efforts circle around what I'm trying to learn; specifically - what is the path LPG takes. I'm familiar with ICE using gasoline, but want to learn/understand the mechanics re propane. Links welcome, thanks in advance.

 

[Tnhawk]

I ran ethanol free gasoline in my dual fuel generator when it was new but after running the gas empty, it has been run on propane since that time. If I bought another one it would never have gasoline run thru it. From the fuel switch forward I I would expect the path to be the same.

 

[MountainGirl]

I ran ethanol free gasoline in my dual fuel generator when it was new but after running the gas empty, it has been run on propane since that time. If I bought another one it would never have gasoline run thru it. From the fuel switch forward I I would expect the path to be the same.

Same here. We're going to pick up another small generator, wish there were "propane only" models. Thanks re fuel switch. My head gets tangled going from liquid to gas delivery.... does the propane condense back down to run through a carb then? Or does it stay as a gas and fed into the chamber ready to go?

 

[TipBledsoe]

I’m no expert on this, but just based on my knowledge of ICE, it does not make any sense to me for propane to route through a carb.

What is the purpose of a carb? To convert a liquid fuel into a gas, right?

Since propane is already a gas, surely the propane is plumbed to the manifold after the carb… Unless there is a need to lean the propane with more air.

 

[no2gates]

Same here. We're going to pick up another small generator, wish there were "propane only" models. Thanks re fuel switch. My head gets tangled going from liquid to gas delivery.... does the propane condense back down to run through a carb then? Or does it stay as a gas and fed into the chamber ready to go?

I am NOT a mechanic, but I believe that the way it works is that the propane goes into the carburetor (I believe it bypasses most of the parts of a carburetor since it doesn't need a float valve and such) as a gas, and gets mixed in with air and then goes into the combustion chamber. It would not condense back to a liquid.

Edit: @TipBledsoe ninja'd me as I was typing this.

 

[MountainGirl]

I’m no expert on this, but just based on my knowledge of ICE, it does not make any sense to me for propane to route through a carb.

What is the purpose of a carb? To convert a liquid fuel into a gas, right?

Since propane is already a gas, surely the propane is plumbed to the manifold after the carb… Unless there is a need to lean the propane with more air.

Running it through a carb didn't make sense to me either. If it doesn't bypass the carb completely, then a carb fail (btdt running w/gasoline) would mean propane is useless also.

 

[Whalercohasset]

It's not a regular carb. Gas goes the usual bowl/float/needle valve route, propane is metered directly into the firing chamber thru a different path in the carb body. There's a switch/lever to choose between the two. The propane setting will still work if ethanol plugs up the gasoline side.

 

[easy rider]

From what I understand, I don't believe it does go through the carburetor, but rather a regulator.

 

[MountainGirl]

Maybe a schematic would be a good idea.
Don't think my guy would be too thrilled with me taking a new gen apart for learning purposes.

 

[Tnhawk]

I am NOT a mechanic, but I believe that the way it works is that the propane goes into the carburetor (I believe it bypasses most of the parts of a carburetor since it doesn't need a float valve and such) as a gas, and gets mixed in with air and then goes into the combustion chamber. It would not condense back to a liquid.

Edit: @TipBledsoe ninja'd me as I was typing this.

Maybe a schematic would be a good idea.
Don't think my guy would be too thrilled with me taking a new gen apart for learning purposes.

I was unable to locate any information beyond the owner's manual for my generator. My plan has always been -if it ain't broke, don't fix it.

 

[easy rider]

Air intake may go through a carburetor, but propane mixes with air in the combustion chamber.

 

[MountainGirl]

It's not a regular carb. Gas goes the usual bowl/float/needle valve route, propane is metered directly into the firing chamber thru a different path in the carb body. There's a switch/lever to choose between the two. The propane setting will still work if ethanol plugs up the gasoline side.

OK. That helps bunches. Thanks

 

[MountainGirl]

I was unable to locate any information beyond the owner's manual for my generator. My plan has always been -if it ain't broke, don't fix it.

Same here, and we've a old dual fuel w/a broken carb, that ran on gas, waiting to be fixed. Time to drag it out of storage, drain everything, and hook up a tank.

Still getting another one, but the old one would be a nice backup.

 

[Whalercohasset]

Just a note, propane requires a specific propane orifice in the carb body. It is NOT usable with natural gas. You would have to swap out the part for that. You can find tri-fuel aftermarket parts for your generator on Amazon. (the one for my 4K Champion only cost $44.)

 

[Tnhawk]

Same here, and we've a old dual fuel w/a broken carb, that ran on gas, waiting to be fixed. Time to drag it out of storage, drain everything, and hook up a tank.

Still getting another one, but the old one would be a nice backup.

I located a replacement carb for my powermate model on amazon for about $60. I hope I'll never need to replace one.

 

[Whalercohasset]

Another note. If you want to save money on a 2nd generator, go to Ebay and look at refurbished Firmans. It's how their factory outlet sells their remanufactured returns and closeout models.

 

[TXAZ]

Does the propane pass through the same carb that the gasoline does? All my search efforts circle around what I'm trying to learn; specifically - what is the path LPG takes. I'm familiar with ICE using gasoline, but want to learn/understand the mechanics re propane. Links welcome, thanks in advance.

Yes it goes through the carb.
The carburetor is used to mix the LP or NG with air, and the Venturi in the carb helps mix that gaseous fuel and air into a more consistent mixture.

I bought a 10kw generator dual fuel (Gasoline / LP), and converted it to handle trI-fuel options (Gas, LP abd Natural Gas). I bought a kit Took the carb inlet apart to add NG and you can see different ports for LP and NG.
The trick is to make sure you’re only using one gas spot a time. Not a problem with generato with a selector switch.

 

[gasgas]

The propane gas uses the carb butterfly mechanism to control the flow and rpm of the propane. Old days basically a hole was drilled in past the butterfly chamber and mixed with air before entering the cylinder; called that a spud-in
There should be a built in pressure regulator in the generator to control the pressure in the spud
Maybe a little different now,but propane is easy to use and control
And not build up of contamination in the fuel system , because the propane is a pure gas and liquid when filled in the fuel cylinder

 

[G O B]

The forklift guy i used to know told me that propane fueled engines never get slugged up. They run a lot longer than gas engines due to not carboning up. The propane does not foul plugs, and oil is honey colored when changed, not black like gas.

 

[Tnhawk]

The forklift guy i used to know told me that propane fueled engines never get slugged up. They run a lot longer than gas engines due to not carboning up. The propane does not foul plugs, and oil is honey colored when changed, not black like gas.

With years of refinery and chemical plants the only issue I remember with propane forklifts was when someone ran out of propane.