As I and my fellow 2012 National Marine Manufacturers Association Innovation Awards judges gingerly picked our way across the chaotic Miami Boat Show floor on the way to the Lehr outboard booth — two days before the show’s official opening — forklifts were furiously slaloming around us and the assembled crates. Lehr (pronounced leer) was unveiling the world’s first propane-powered outboard engine, and, quite frankly, we were prepared to be underwhelmed. After all, these were 2.5 and 5 hp outboards that had obviously been jury-rigged to burn propane. But as we made our way there, our attitude began to change; we noticed that every combustion engine-powered forklift inside the building was running on propane. By the time Capt. Bernardo Herzer (Lehr’s founder and CEO) gave us his presentation and ran the engine for us (again, inside the building), we knew we had found our Ecological Winner for the 2012 Innovation Awards.
What prompted Herzer to go propane? Going back a few years, he found himself at sea in the employ of Her Majesty’s Service studying the effects of commercial fishing in the North Sea. On board his diesel-powered research vessel, he noticed a couple of things. The portable generators that fueled the compressors and scientific equipment were gasoline powered, and care was needed to prevent potentially fatal accumulations of carbon monoxide. He also noted that the ship’s stoves were propane, which could safely be burned inside the galley. So, he thought, wouldn’t it make sense to power our generators the same way?
Another of Herzer’s motivations came from watching commercial fishing’s adverse impact on the environment. He’d recently had a son, so he wanted to do something to effect change, so the next generation would inherit a greener planet. Realizing that propane was a much cleaner source of energy that virtually eliminated the potential for accidental spills, Herzer started looking at high-polluting gas engines he could convert to propane. The low-hanging fruit proved to be garden tools such as weed-whackers, trimmers and blowers whose two-stroke engines can spew out as much pollution in one hour as eight cars traveling 55 mph for an hour. According to the EPA, gas-powered garden equipment use accounts for 5 percent of all the United States’ pollution. According to Herzer, the Lehr outboard produces 97 percent less particulate matter than gas-powered engines.
Today, Lehr produces a full line of garden equipment, including lawn mowers, and generators, so taking the next step to outboards wasn’t an illogical move. The first generation of outboards includes a 2.5 and 5 hp four-stroke motor, in both 15- and 20-inch shaft lengths. Weighing just 52.8 pounds (long shaft), the 5 hp is the lightest outboard in its class, by a margin of up to 9.5 pounds. It’s a fairly conventional engine with a single cylinder with a 112cc displacement, which is the smallest in its class.
When propane is pressurized, it’s in a liquid state, which is more compact, but when the pressure is released it turns to vapor, which also makes it spill-proof. Even if it is vented into the atmosphere, it’s not a problem since it’s not classified as a greenhouse gas. Because propane is under pressure, Lehr outboards need a different fuel-delivery system that includes a special carburetor that doesn’t have a choke, so we were able to start it easily with one pull. A major plus is that propane doesn’t degrade with time, like gasoline or ethanol-laced gasohol, which has damaged many small motors throughout North America.
Propane for a Lehr can be stored in a regular 20-pound-capacity barbecue tank, but a better alternative is a fiberglass or composite tank, which only weighs around 12 pounds. You can even screw one of those 1-pound camping tanks right into a fitting in the engine’s cowling.
The Lehr outboard is very solidly built using high-grade metals such as stainless steel and bronze, and the fit and finish is good. Lehr produces its own engine block, so quality-control issues are within the company’s sphere of influence. Pricing is comparable to conventional outboards ($1,630 for the 20-inch, 5 hp model at West Marine), and based on current gas/propane pricing and fuel efficiency, your fuel bill will likely be less. The only downside is that the motor we tried seemed noisier than other portables I’ve tested, although this isn’t surprising, since other builders have had decades to figure out how to ameliorate noise.
Lehr plans to build engines up to 175 hp but was wise to start small in order to work out any issues. So is propane in our future? The U.S. and Canada have a vast, underutilized supply of propane (aka LPG, liquefied petroleum gas). Throughout the world, propane is the third most popular transportation fuel, so this isn’t a huge reach, and there are filling stations at many hardware and home improvement stores. On “Jay Leno’s Garage,” Herzer said that even if every car in the U.S. switched to propane, we would have a domestic supply that would last 180 years.