# Propane outboard



## hainess13 (Jun 25, 2009)

Kinda excited about this one...

LEHR - Environmentally Friendly Technology

http://golehr.com/docs/specs/specs_2.5.pdf

2.5 hp or 5 hp for a raft? No gas - same fuel as our cook stove - only problem is you can't refill your propane bottle with solar panels!


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## buckmanriver (Apr 2, 2008)

*Bottom line*

How much?


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## yesimapirate (Oct 18, 2010)

Dealers in CO?


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## Billy Goat (Feb 3, 2011)

Why not use a conversion kit? It is not new science, many companies produce the necessary kits to convert most kinds of gas motors to propane. If you are the man with carburetors, you can probably do it in 2 hours or less. It has to be a cheaper route than a new motor. I do believe they are only for 4 stroke motors though.


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## BCJ (Mar 3, 2008)

I've looked into these and they are priced about the same as 4 strokes of similar size and HP. Right now they make a 2hp short shaft and a 5HP long or short shaft. There are some videos etc. at the LEHR website.


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## MT4Runner (Apr 6, 2012)

Billy Goat said:


> Why not use a conversion kit? It is not new science, many companies produce the necessary kits to convert most kinds of gas motors to propane. If you are the man with carburetors, you can probably do it in 2 hours or less. It has to be a cheaper route than a new motor. I do believe they are only for 4 stroke motors though.


Yeah, you can't premix oil with propane.
You might be able to use a newer oil-injected 2-stroke, but who wants to smell a 2-stroke on a river trip?!

Newer 4-stroke motors aren't cheap, either, but they burn really clean, and they're becoming common enough that they're coming down in price. You need a propane regulator that turns liquid propane into propane gas, and you need a mixer that takes the place of the carbueretor and mixes air with the propane gas.

Most propane "fuel" tanks have a dip tube and draw liquid propane off the bottom of the tank. If you ran it off a barbecue tank, I'm not sure if you'd pull it so fast that the tank would freeze up. With the relatively small amount of fuel used by a 2-5hp engine, it's possible you might be able to run a 20lb BBQ tank and gaseous propane and skip the regulator. Without the regulator, you'd want some sort of solenoid valve that would shut off the flow of propane if the engine died--both to save fuel and prevent pollution, and to also minimize the risk of a KABOOM!


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## jgrebe (Jan 16, 2010)

*2 stroke conversion*

I converted some 2 stroke engines in the Phillipines to burn butane. Same basic thing. The kits were from India and were about $100. Uses a small oil injector pump and a tank of two stroke oil. 4 strokes would be the same regulator set up as converting a car ( I've done a bunch of these). US kits are about $400 but can probably find cheaper stuff in India or somewhere. Anybody serious about this and I can walk you through the process


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## Billy Goat (Feb 3, 2011)

All 4runners concerns are addressed in the kits. They are about $200 and available for most enginges from many suppliers. Some require drilling of the fuel port on the carburetor and some don't. The nuts and bolts list is 1)High pressure propane hose assembly 2)Regulator 3)Fuel supply line and 4) Intake adapter. That's pretty much it with a few odds and ends fittings. Not really practical in this setting but most of these conversions will allow for the use of natural gas as well.


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## MT4Runner (Apr 6, 2012)

I didn't realize that kits were available for outboard applications--very cool! I'm more familiar with automotive applications.
Do these kits use BBQ tanks (gas) or forklift tanks (liquid)?

It would be very nice to have the dual-use convenience of a BBQ tank.
(You can't connect a forklift tank to a BBQ--the regulator isn't designed to vaporize liquid propane.)


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## richp (Feb 27, 2005)

Hi,

I actually converted a pickup truck to propane years ago. As a dual fuel vehicle it was pretty neat -- flip a switch under the dash and you had your choice of fuels. But the large crossways mounted propane tank took up about 1/5 of the bed in order to get range equivalent to what was in my gas tank.

And that -- I think -- is the downside here. For short journeys and specialized uses, this might be something to pursue. But propane has a great deal less BTU content than gasoline, and storage in heavy cylindrical tanks is a downer. The result is that to get equivalency in fuel range for a long trip, you would have to carry a rather large number of propane bottles.

I'm sort of in the "the new four strokes are sufficiently quiet, non-smelly, and efficient to do the job" camp.

FWIW.

Rich Phillips


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## buckmanriver (Apr 2, 2008)

*How much do they cost?*

Who found a number on price?


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## restrac2000 (Mar 6, 2008)

Hey Rich,

How much propane would it take to push a raft the last 20 miles in Cataract or something similar? 

I personally hate carrying gasoline. Its horrible for the environment when spilled (we spills millions of gallons a year as Americans), from what I understand its more volatile, isn't as physically stable for storage (I can store propane for ages compared to gas) and requires greater care in storage. 

Given the chance I would prefer to start with a propane engine if its fuel consumption is manageable. I currently lack an outboard but I am looking for one for shorter trips, like I mentioned with Cataract or the lake section of the Owyhee. 

Thoughts? This idea is intriguing to me.

Phillip


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## BrianK (Feb 3, 2005)

I searched for it and it looks like you can get them for just under $1k for the 2.5 hp and $1.5k for the 5 hp.

I have been looking for a motor for a while - mostly for cataract trips - and I have the same questions as above. How much propane would it take to get out of cataract?

Also, is 2.5 hp enough power? I have only used a motor once on the river and it was a 15 hp motor on lake powell. We had like 10 rafts and we were flying across the lake, but I am not sure if 2.5 would be enough. 

A rafting company I worked for had a propane school bus and I loved it. It worked great until you had to go up hill.


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## RutRow (Apr 21, 2011)

wont a propane motor require you to carry alot more weight than gas. Doesn't gas have much higher energy denstiy not to mention a heavy propane tank?

anyone have actual figures?


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## colorado_steve (May 1, 2011)

aren't you suppose to start lpg conversion engines/cars on gasoline and then switch over to lpg once the motor is running? not 100% about this, but might be something to think about


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## richp (Feb 27, 2005)

Hi Restrac and Brian,

Too many variables to know for sure. How many boats are you pushing out? What type and configuration of the lash-up? What are the wind conditions? What's the lake level? How fast are you going to try to go? What size motor will you have?

My personal data here is pretty narrow-range. Over the years, I have pushed a lot of strapped-up rafts on the bottom end at Westwater. The one time I did a calculation on it, I figured I was getting about 25 miles per gallon -- often with as many as 3-4 other rafts lashed to my cat. Down at Cat, I once pushed a single 20' Jack's cat from just below the last rapid (#28? #29? at the time) all the way to Hite with a Honda five, and not much wind. Cost me about a gallon and a half of fuel, and that was just one boat -- albeit a big one with a smallish motor.

My personal comfort level to get off Cat would be pretty high if I had a five horse gas four stroke and a three gallon fuel tank. So if you consider that propane is maybe 20-30% less efficient than gas, you're crudely in the range of five gallons of propane to have a safe margin -- again with a lot of recalibration for all the factors I mentioned up above. 

That hardly qualifies as much more than a scientific wild-ass guess. But hopefully the company could provide a prospective customer with some fuel consumption data to start making a real-world estimate.

FWIW.

Rich Phillips


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## BCJ (Mar 3, 2008)

I'm not sure of his numbers, but I think RichP is focused on the right question -- efficiency. Not to say that a small sacrifice in efficiency isn't worth the environmental savings, but, basically, it seems these propane outboards cost about the same as the modern 4-stroke outboards and do have a lot of mechanical and environmental advantages, so the question is, how far can one go on a pound of propane vs a gallon of gas and what does that cost? I am intrigued. If anyone has looked into this further, let us know! (Hi Rich!)


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