Propane Fueled Outboards

[Nomad Willy]

They VIBRATE too much.

Like Skipper Dude I've got a 2hp Yamadog. Don't remember the weight but it IS light. And you can lay it down any which way. I have 4 stroke OBs but I prefer 2 stroke.

I have a 40hp Evinrude e-tech (2 stroke) and it's been great but it weighs almost as much as a 4 stroke. Burn's amazingly little fuel ... again no numbers as I haven't kept track and part of my low burn experience is because I run a fairly light aluminum skiff and I run at about 18 knots .. just over the hump.

But if you have a new hybrid car perhaps the propane OB is for you.

I don't see any really compelling reason to buy a small propane OB .. unless you're just the kind of guy that has to have the latest brand new thing on the market whether or not it is actually better than the tried and proven. A mid-size or bigger propane OB would (in my opinion) really have some value worth looking for.

 

[ancora]

My 27 year-old Mariner 2 stroke 2 HP outboard weighs all of 19.84 lbs. As long as I can keep buildin' up the lower end with JB Weld I'll stick with it.

 

[Forkliftt]

They VIBRATE too much.

Like Skipper Dude I've got a 2hp Yamadog. Don't remember the weight but it IS light. And you can lay it down any which way. I have 4 stroke OBs but I prefer 2 stroke.

I have a 40hp Evinrude e-tech (2 stroke) and it's been great but it weighs almost as much as a 4 stroke. Burn's amazingly little fuel ... again no numbers as I haven't kept track and part of my low burn experience is because I run a fairly light aluminum skiff and I run at about 18 knots .. just over the hump.

But if you have a new hybrid car perhaps the propane OB is for you.

I don't see any really compelling reason to buy a small propane OB .. unless you're just the kind of guy that has to have the latest brand new thing on the market whether or not it is actually better than the tried and proven. A mid-size or bigger propane OB would (in my opinion) really have some value worth looking for.

Eric- the reason I would consider the propane outboard is to get away from old gas issues. It seems on my 3.5 four stroke I just don't seem to run it enough to avoid carburetor issues.

 

[HopCar]

My new Practical Sailor magazine arrived today. They did a test of the Lehr propane outboard. They confirmed a couple of my impressions. The engines are very easy to start and the cover latches leave something to be desired. They also confirmed Lehr's claim that the 5HP will run on one of those one pound propane bottles for half an hour at WOT and a lot longer in typical use.

 

[Codger2]

Eric- the reason I would consider the propane outboard is to get away from old gas issues. It seems on my 3.5 four stroke I just don't seem to run it enough to avoid carburetor issues.

My sentiments exactly, not to mention that I already carry propane which can be stored indefinitely without the fuel degrading.

 

[JD]

My sentiments exactly, not to mention that I already carry propane which can be stored indefinitely without the fuel degrading.

This is going to turn the small outboard industry on it's ear once they work out the kinks and it doesn't seem like they have all that many to work out.

 

[Nomad Willy]

JD wrote;

"This is going to turn the small outboard industry on it's ear once they work out the kinks and it doesn't seem like they have all that many to work out."

Well if that actually happens it'll solve the fuel availability problem. Walt makes good points as usual but I don't think it will happen. If it does it will be because it's a new thing and we Americans LOVE new things. I'm sure it won't make it in 20hp and bigger OBs as it's common knowledge that propane fueled and converted gasoline engines burn more propane than gas. I know the difference is very small but that's only because I've got lots of experience running propane engines. I think it'll be about as popular as the Wankle engine was.

By the way JD I don't think there are any "kinks". It's well proven technology.

 

[JD]

By the way JD I don't think there are any "kinks". It's well proven technology.

I agree and by kinks I meant the hatch latches and portable propane tanks that fit under the seats of the dink. Not real mechanical kinks.

 

[HopCar]

JD, The latches really aren't bad but they were showing improved latches on the 9.9 introduced at the Ft. Lauderdale show. I hope to get my 9.9 at the Miami Boat show in about three weeks.
I plan to use a 10 pound horizontal aluminum tank. It's only 11" high. I should get about 2.5 hours at WOT and twice that if I throttle back a little.

 

[Codger2]

I'm sure it won't make it in 20hp and bigger OBs as it's common knowledge that propane fueled and converted gasoline engines burn more propane than gas. .

I agree! If the 9.9 turns out to be the highest horse power the Lehr offers, it certainly isn't a failure & will be a slick engine for the dinghy. I spent about an hour a few months ago going over one at West marine. Very impressive!
It even has a fitting that you can plug your barbecue bottle in to for extended range. (It does require, however, a very long hose to reach from the barbecue to the dinghy. )

 

[FlyWright]

It does require, however, a very long hose to reach from the barbecue to the dinghy.

LOL!

I'm a big fan of propane. I have it on the boat for my stove/oven, my grill and my portable heater. I carry gas for my Honda eu2000i generator and my Honda 2HP outboard. There are propane conversion kits available for the generator that I'm considering. I'm now wondering is something similar is available for our gas outboards. Hmmmmm...

Honda EU2000i generator operating with propane - YouTube

 

[HopCar]

Flywright, there is nothing technical preventing converting gasoline outboards to propane but you would lose power. The Lehr engines take advantage of propanes 110 octane rating to run at higher compression ratios than gasoline engine. When you buy a five horse propane outboard you get five horses. When you convert a 5 hp gas engine to propane you get less than 5HP. I'm not saying it's not worth doing, I have a generator that will run on gasoline or propane. It puts out less power on propane but I have never put gasoline in it. I accept the lower output in exchange for reliability. If Lehr ever makes propane portable generators, I'll be first in line to buy one.

 

[Codger2]

There are propane conversion kits available for the generator that I'm considering.

Honda EU2000i generator operating with propane - YouTube

WOW! I did not know this! We are talking thousands of dollars less for a Honda EU 2000 that runs on propane and with a Lehr 9.9 you have the outboard and the generator without the need for gasoline!

Edit: I think I'm going to do it (generator) and wait for the Lehr 9.9. I'll tow the dinghy to start with.

 

[FF]

A second advantage to the propane non poisonous exhaust is the clean fuel allows service life comparable to Diesel engines.

3X longer than most gasoline units.

Another plus for propane is the fuel evaporates from the carb , so the unit will start after 6 months or a year of non use , unlike most gasoline items.

 

[Nomad Willy]

HopCar wrote;

"When you buy a five horse propane outboard you get five horses. When you convert a 5 hp gas engine to propane you get less than 5HP."

How do you know that unless you convert the 5hp propane OB to gasoline? With the dual fuel engine you must run with the gasoline ignition timing that is considerably different than the optimal propane timing. The gas engine would knock and ping w propane timing at the mid to low end and fall very flat (and not develop as much power) at the high end. To tell which engine is most fuel efficient you'd need to get the dual fuel engine out of the picture. So if you converted that 5hp propane OB to gas you'd need to retard the timing a lot at lower speeds and slightly advance it at the top end. And I think the resulting gas 5hp OB would be something more than 5hp. I have a book on propane conversions and could look that up if I could find the book. Haven't thought about it for years but I think that's the way it stacks up.

Rereading your post Hop I see the bit about the compression. The dual fuel engine would need the gas compression but the propane engine could run higher and that could put it over the top. NG is different also.

 

[JD]

HopCar wrote;

"When you buy a five horse propane outboard you get five horses. When you convert a 5 hp gas engine to propane you get less than 5HP."


Rereading your post Hop I see the bit about the compression. The dual fuel engine would need the gas compression but the propane engine could run higher and that could put it over the top. NG is different also.

Hopcar was referring to an engine designed from the ground up as Propane. Thus a true 5hp. Just as a gas 5hp is a true 5hp.

 

[HopCar]

"When you buy a five horse propane outboard you get five horses. When you convert a 5 hp gas engine to propane you get less than 5HP."
Hi Eric, When I said that I was talking about just taking an engine designed to run on gasoline and running it on propane. Seahorse and Flywright were talking about converting the little Honda generator to propane. My point was that it wouldn't put out it's rated wattage after being conveted to propane.

"How do you know that unless you convert the 5hp propane OB to gasoline?"
Why would I need to do that? I have converted two gasoline generators to propane and they do lose some power. I think it's a good trade for improved reliability.

I don't think you could even convert a Lehr propane outboard the gasoline. They run at too a high compression ratio for pump gasoline. I hadn't even thought about the timing. If you did go to the trouble of changing the pistons to lower compression and adjusted the timing you might get more power out of a propane to gasoline conversion.

In regards to your earlier comments on propane engines not likely to get bigger than about twenty horsepower, I think you're right. Anything bigger than that will need built in tanks to get useful range. For that to happen you need a much bigger propane selling infrastructure. To begin with marinas would need to start selling propane next to their gasoline and diesel pumps.

On the other hand propane is a great fuel and a lot of boats use it for cooking now.
It doesn't cost much for a marina to install a propane fueling station. The propane company pays for everything but running electricity to it.

Do you carry propane and gasoline on Willy? Propane for cooking and gasoline for the dinghy?

 

[Nomad Willy]

"I don't think you could even convert a Lehr propane outboard the gasoline."

Sure you could. You'd just have to follow directions by somebody else or do your own research. With a proper conversion all such things like compression and ignition timing would need to be dealt with.

I do, however agree w you that propane conversions are shy 2 to 5% of what they were as gas engines.

"Do you carry propane and gasoline on Willy? Propane for cooking and gasoline for the dinghy?"

Yes. Guilty as charged. We have a propane stove w oven and one hose connection inside the boat. We run a 2hp Yanaha OB also. I think w a propane OB we'd still have two separate sources of fuel. Would you?

JD,
Yes of course. There are propane engines, gasoline engines and dual fuel engines.

 

[HopCar]

Hi Eric, Thanks for the excuse to stop working and play on the internet!

I think we can agree that it is easier to run a gasoline engine on propane than a propane engine on gasoline.

"Do you carry propane and gasoline on Willy? Propane for cooking and gasoline for the dinghy?"
I guess what I meant to ask was do you see any advantage in eliminating gasoline as a fuel you need to carry on Willy. I also sometimes need to carry three fuels on Possum but my cooking fuel is alcohol. When I switch to a propane outboard I'll still need three fuels but I don't like handling gasoline. It smells bad, it's easy to spill, it stains fiberglass. For me a propane outboard for my Avon looks like a good choice.

"JD,
Yes of course. There are propane engines, gasoline engines and dual fuel engines."
Actually tri-fuel engines. My home generator would run on natural gas as well. If I had an NG pipe to my house I would certainly do that.

 

[3dog]

I have owned a 2000 Merc 25 hp, a 2002 Merc 6 hp 4 stroke and now a Tahatsu 9.8 4 stroke and all needed to have the jets cleaned at least twice or more during the season (Maryland). I have tried the suggested fuel additive, changed the fuel every month, put an in line water separator, run the carb dry after each use and still get clogged jets. I would love to be able to convert my 9.8 to propane and have seen youtube videos of it being done but have yet to find out how to get a conversion kit. Anybody out there actually converted an outboard????

 

[HopCar]

3Dog, I once had my local lawn mower shop convert a generator to propane. They knew where to get the kit.

Why don't you unload the Tahatsu and buy a Lehr 9.9? If you just hang a propane carburator on a gasoline engine, you'll lose power. An engine designed to run on propane will put out the rated power.

 

[3dog]

Not concerned about losing power, just want to get away from ethanol. I have a remote steering outboard and don't want to pay @$3k to replace what I have.

 

[Nomad Willy]

3dog,
The propane engine runs on a different ignition curve than gas so a conversion lacking the ignition changes would not run properly. But it would run. You could just adjust the timing until you achieved the best results.

HopCar,
For my rubber duckie the very light gas 2 stroke Yamaha works well. I don't think we had alcohol in our gas in Alaska ... haven't had any storage and crud in the carbs but I know we have alcohol here in Wash state so I may be interested in propane in the future. I've seen the propane OBs at Harbor Marine in Everett WA. What I more likely will want propane for is a get home OB.

 

[HopCar]

" What I more likely will want propane for is a get home OB."
Eric do you mean to push Willy a few miles? How many horsepower do you think you'd need?

 

[Nomad Willy]

Five to ten.

 

[HopCar]

Eric, I think a propane outboard would make a good get home engine. It wouldn't get used much so storing gasoline would become an issue but propane doesn't go bad in storage. A 20 pound barbeque tank would run a 10 hp propane powered outboard about 5 hours at WOT. That should get you somewhere.