Join Date: Jul 2013
Location: Miami Florida
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Re: Propane Powered Outboard Engine Experience??
I'm a Lehr dealer and I'll try to answer some of your questions.
Reliability: The first container load to hit the US were not good. Lehr just gave everybody a new one. I'm afraid it hurt their reputation. The ones I'm getting now are great.
Service: Any mechanic that can work on a Yamaha can work on a Lehr. Even some of the parts are interchangeable. The propane handling part of the system is very reliable, requires no maintenance and if it does break, you just replace it using a couple of wrenches. There are service videos available on line that address the most likely problems to come up.
Starting: Lehr has got to be about the easiest to start engine out there. The trick is to get the air out of the hoses before you start to pull the rope. There are very clear instructions on how to do this on the Lehr website.
Fuel density: Propane is less energy dense than gasoline but it is higher octane. The higher octane allows the Lehr to run at a higher compression ratio than a gasoline engine and is therefor a little better at using the available energy.
Safety: Propane needs to be stored like you would store gasoline. Propane, if spilled, would dissipate to non explosive levels faster than gasoline. It is a lot cleaner to handle.
Range: Lehr engines use about a quart (pound) of propane per hour for each 2.5 hp.
In other words the 2.5 will burn one of those 16 oz. Propane bottles in an hour at wide open throttle. The 5 will burn it in half an hour. The 2.5 will run at WOT for twenty hours on a typical barbeque tank. If you run at 3/4 throttle fuel consumption drops dramatically.
Converting to propane: You can easily convert most gasoline engines to propane but if you don't change the pistons to increase compression, you'll lose power. I don't know of any kits to convert out boards but I've seen outboards that have been converted. I have an emergency generator set up to run on gasoline, propane or natural gas. It puts out about 6kw on gasoline but only 5.5 on propane. I've never run it on gasoline because I want it to start when I need it. I start it once a year at the start of hurricane season and it's started every year for about ten years now.