Propane conversion on my 425

[CreativeGuy]

Greetings.
I am just loving my new 425. I'm thinking about the possible benefit of converting it to run on Propane. I converted my 3500 watt inverter gas generator to run on Propane and am very happy. I don't have to worry about gas going bad or gumming up sitting in the tank. The oil in the engine stays cleaner for much longer. Propane essentially doesn't go bad so it certainly made sense for a small engine that doesn't get run very often. It cost about $300 to do the conversion but I only paid $200 for the generator (un-used) at an auction.
I know gas is a bit more efficient than propane but propane is much cleaner and safer to store.

Has anyone thought of converting their PT to run on Propane? There is a local propane company which will do the conversion on the 425 for around $2,000.00 which includes the tank and mounting bracket (over the engine cowling)

Thoughts?

Cheers,
Steve

 

[BobRip]

Interesting. What affect will that have on the horse power?

 

[CreativeGuy]

My understanding is that there would be a slight drop in HP and it runs a little hotter. But the engine runs so much cleaner that the oil will not need to be changed as frequently.

 

[woodlandfarms]

I would not let oil cleanliness be the decision that takes you over. Higher heat in a pt is a bigger issue I would want to avoid. But I know noting about propane or conversions.

 

[Gravy]

Converting to propane will result in significantly less horsepower and range, and refueling will require having spare propane tanks. Propane refills are not as convenient as gasoline refills. That translates to more expense and hassle if you use your PT daily. OTOH, as you mentioned, propane doesn't go bad quickly like gasoline.

If it seems to make any sense for your situation, give it a try and report your results.

 

[BobRip]

How would it affect cold starting?

 

[MossRoad]

Enough about gas going bad quickly. It doesn't. I've run gas with 10% ethanol in every gas powered vehicle and piece of equipment since the early 80's. I've had ONE fuel line go gummy in a chainsaw that sat for a year. Other than that, I've had NO fuel related issues. NONE! that I can attribute to gas going bad or ethanol in 35 years.

I keep three 6 gallon cans of gas. That's 18 hours of run-time for my PT, which equates to about 18 weeks, as I average 50 hours per year, or one hour per week. So my fuel sits around for 4 months at a time minimum, longer in winter. Unless you're going to let it sit for a year at a time, you'll run your gas through it well before it has a chance to go bad.

I can't see spending $2000 on a propane conversion. That's about 750 gallons of gas at $2.50 per gallon, or about 750 hours of run time. How much does propane cost per gallon equivalent of energy?

The gasoline gallon equivalent of propane is only a tad over 80%.
Gasoline gallon equivalent - Wikipedia

There's only 4.7 gallons of propane in a 20 pound tank. You'd have to keep several tanks around. Also, those tanks don't typically have a fuel gauge that's accurate. I see being out in the woods and walking back for fuel and having to carry a full 20 pound tank back to the woods. At least I can see the fuel level in my PT gas tank, and I can carry a 1 gallon can of foot should I run out.

If you're talking about propane tanks like on forklifts, those are 33 pound tanks, I think. Those would have about 8.5 gallons, so you might get some decent run times out of those and some of those have sort of accurate fuel gauges.

I don't know. To me, it doesn't seem economical, convenient, or practical. Propane fueling stations for 33 pound tanks are few and far between, while there's a 7-11 on every block( hahahaa major exaggeration ). A 33 pound tank costs about $200. A plastic gas can is $20. I don't know if there's an economical exchange program for 33 pound tanks. I know we had a rack of them at my employer that were auto stocked by the supplier.

Put it all to spreadsheet and run the numbers. I think you'll have a machine with significantly less power that uses a bit more fuel, or, if you bump up the power, uses significantly more fuel that is less convenient to obtain.

Propane is a lot safer to store than gas, I'll give you that. And if you have to store gas for more than say, 6 months, just put in some stabil and it will be good for more than a year.

Again, I think you'll rotate through your gasoline much faster than it will take for it to go bad.

Just my opinion. I'm know there's tons of TBN members that don't agree with me. A lot of them are always talking about adjusting the carbs on their saws, too. I never adjust my saws, weedeater, string trimmer, etc... they just don't need it. Set it and off you go. Heck, I rarely adjusted the carbs on my drag bike once I got them set! Enough with the tinkering!!! :laughing:

 

[jaxs]

I've owned propane farm tractors and operated some belonging to others for several years. It's normally a little cheaper than gasoline and never go's bad sitting in tank. Better governer response coupled with no pre-detnation more than offset's the slight difference in HP. If you don't have hard valve seats and run lead substitute in no-lead,that will be a problem. Your storage/nurse tank must be equipped with a "wet line"to draw liquid or be equipped with a pump. I've always had a wet line. I made up a line that alow's fueling from a grill bottle. Some will say it's impossible to get liquid from a grill bottle because opd close's when tank is inverted. Not so,and if you want to see for yourself,open the valve with tank upside down.

 

[MossRoad]

Yes, a gas engine rated at 25hp will have the same HP as a propane engine rated for 25hp. However, there's no denying that propane has 27% less energy per gallon than gasoline. If the OP takes his 25HP gas engine and has it converted to propane, he'll have to bump up the propane consumption significantly to get back to 25HP output. He'll get less MPG using propane than gasoline. So he has to put pencil to paper to see the price difference.

Honestly, for a machine that's probably only going to run less than 100 hours per year, we're talking about less than 20 bucks per year in increased fuel costs I'm guessing.

 

[SpringHollow]

I hate 10% ethanol in small engines. Part of the issue is that it frees up stuff that regular gas did not which then clogs the carbs. A gas can does not get filled without adding stabilizers etc to it even prior to 10%. I never had to rebuild a carb prior to 10% and I have done lots since, even on engines that have only been used with 10%. It got to the point where whenever I bought a small engine piece of equipment, I would pick up a rebuild kit for it as well. We now have a supplier of ethanol free gas which I now pay extra to get for all of my small engines. Those carbs have not had to be rebuilt. I have had zero issues with 10% in my vehicles.

I started an old pickup once that had 35 year old gas in it since the seller did not want me draining the tank in his garage. I was quite surprised to have no issues with that tank of gas. All I needed was a spare battery to get that truck running.