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.

 

[CreativeGuy]

MossRoad, you make a lot of great points about gas vs propane. Especially considering that I will probably be using "Artie" even less that most of you guys. Right now I would be better off putting the money into a flail mower option. (Which really is a priority for me)
As for Gas, I only use non-ethanol gas in any of my small engines including the 425.

Cheers
Steve

 

[MossRoad]

It's a waste of money to pay extra for ethanol free, but that's just my opinion. Everything I own is designed to run on E10. I'll keep using it. Good luck to you, though. To each his/her own.

 

[ponytug]

While a 25HP propane engine and a 25HP gasoline engine have the same HP, converting a gas engine to a propane fueled engine does cause a drop in HP. Basically, you can't get enough fuel into the engine.

If it were me, I would run the PT for awhile and see if gas getting old becomes a problem. A propane carburetor ($190 on eBay.) is easy to buy and install, as would a propane tank. (For a lot less than $2k!) Switching to propane will clean out any residues.

In the old days, there was a substantial price advantage to propane, but in most of the country, you pay about the same per BTU.

I haven't had a problem with E10 gas, but I do add Stabil to the gas, and run SeaFoam/Carb cleaner through the engines regularly. I also try not to leave gasoline in small engine tanks.

FWIW: I did recently switch to NATO (Wavian) jerry cans, which seal much better than plastic ones. I got tired of plastic cans ballooning or sucking themselves into little raisins. I won't go back. It is so much nicer to be able to fill cans and put them in the car, and not have the smell of gas or diesel in the car afterwards. They also seal better against water, and keep the butane from leaking out of the gas.

All the best,

Peter

 

[MossRoad]

Yeah, I can't see where it would cost $2K either. You can purchase a whole Kohler 25hp engine for LP for about $1700.

 

[marrt]

I hate 10% ethanol in small engines.

I have to agree with SpringHollow on this one. I have more than 20 gasoline engines (not counting vehicles) and I'm constantly cleaning carbs. I bought a large Dewalt power washer a couple years ago and have already cleaned the carb twice. When an engine won't run smooth and "hunts" for the right RPM, it's time to break out the ultrasonic cleaner and illegal carb cleaner. This seems to be especially common on Honda engines for some reason.

I think we have multiple problems colliding here. To hit emission targets in CA, I think modern carbs are likely built to a different level of precision inside. Add to this the propensity of ethanol fuel to gum up as it ages, plus act as a solvent to gaskets and other stuff and you have the recipe for a big problem.

My father has a very old tiller with a Briggs and Stratton engine and we've never been into the carb. Growing up, we never had the problems that are common today. Then again, you could smell more gas than smoke from the exhaust when these things were running.

This topic reminds me with the government's effort to stop fuel evaporation for common fuel cans. I have several metal fuel cans with a spring loaded lid. There's no evaporation and the lid (and metal can) helps keep the fuel fresh. On the other hand, when using the can, I spill FAR more fuel than when using an old can. Since there's no vent, the can can't get air when pouring and splashes all over the place. Yet another example of good intentions actually making the core problem worse.

 

[ponytug]

I agree with you that the higher tolerance probably don’t help. I also think part of the challenge is the higher oxidation potential of E10 fuel compared to older fuel.

You can try one of these, as they seal better;

If you use the CARB spouts, you will not spill much, if anything. The NATO spouts are much faster, but require some hand eye coordination not to spill.

All the best,

Peter

Just in time for New Years, you can get four for a little more than $220, plus a nozzle for $25. Not super cheap, but then it might be worth it not to be cleaning carbs....

 

[cqaigy2]

I'm pretty lucky as i don't seem to have any problems with the older or new engines on the ethanol laced gasoline, except when i forget to turn the fuel lever to the open position. I use plastic gas containers which i think reduce condensation of moisture and pretty religious about the gas treatment. Moisture in this climate is pretty high, even during our drought cycle. I have propane for my generator which doesn't get much use and i think it keeps better and it doesn't get very cold here.

 

[MossRoad]

I've got 3 old 6 gallon Blitz plastic gas cans with snap-on vent caps. The spout stores inside the can. At one point in time, Blitz was the world's largest gas can maker. They got sued out of business due to several people using gasoline to start fires, and having the cans explode. Google Blitz and lawsuits some time, its and interesting read. A sad combination of bad decisions by the gas pouring crowd and no flash arrestor on the spouts of the cans. Anyhow... the cans are probably 25+ years old now and still function fine. And as I've mentioned while beating my dead horse, I've not had any ethanol related issues using E10 in 30+ years.

How come so many folks report ethanol issues and issues of gas going bad? Heck, I've got an old '85 chevy pickup with a carb that sat in my back yard since around 1997. Every year or two I'd start it up and move it so I could mow the trees growing out from under it. For about 15 years it started with just a shot of starting fluid and a battery jump. That was sitting for 15 years with E10 in it. It doesn't start now due to I've pilfered too many parts off the engine.

Maybe its a regional thing and fuel additives?? I don't know. I can't think of any of my friends in this area that have had fuel issues and I know a LOT of people with a lot of toys/equipment. :confused3:

 

[jaxs]

It does seem odd how some are plagued by E-10 problems while others can't cause a problem even when they try.
So far,the only commonality I find is that people who experience no problems with E-10 often swear by Harbor Freight tools. If an engine has sat with E-10 and hasn't been run for more than a couple of years I almost always have to clean,repair or replace before getting it back in operation.

 

[MossRoad]

Heck, my in-laws gave us a 2.5hp Briggs engined lawnmower when we got married in 85. I NEVER changed the oil (just topped it off occasionally), never changed the spark plug, tapped out the air filter once a year, and never ran it out of fuel. Left it sit all winter long. After about 10 years of it starting 1st pull every spring, we started making a ritual of it, calling the wife and kids out to see of the mower would start first pull. I'd give it about 20 primes and yank the cord... BRRRrrrrrrrr! 1st pull.... 20+ years. I finally had to retire it when the deck got so cracked I couldn't repair it anymore...

Anyhow, 20+ years of E10, tank never drained, 1st pull starting... must be a fluke.