I first met John DeFilippi, owner of ecoLogical Lawn Care, at the Green Days event in downtown Boulder a few months ago.  He was using a variety of electric implements for landscape work but was concerned that his gas-burning commercial mower he was using for larger jobs just didn’t fit the ecological model he was trying to portray with his business.  I told him that we could convert that mower to propane and he wouldn’t have anything to worry about.  It took a few weeks for the green light to order parts, and then a few weeks more for the parts to finally arrive but we now have one of the cleanest running commercial walk-behind mowers in operation.  The kit consisted of a special carburator jetted for propane, a pressure regulator, a vacuum shut-off valve (assures that propane can only flow if the motor is turning and creating vacuum) and a variety of fittings and hoses.  The installation was a straight forward process of removing the gas tank, fuel lines and stock carburator and replacing them with the propane specific parts.  Finding the right locations to mount the regulator and shutoff valve took some head scratching but the end result is clean and elegant.  We borrowed a propane tank (John’s tank will arrive tomorrow) because we just couldn’t wait to test it.  Our hearts sank initially as we just couldn’t get the motor to fire.  Once we realized that the propane tank valve needed to be opened things started looking up quickly.  The motor runs smoothly and the exhaust now has a slight propane smell rather than the noxious gas smell.  The system is EPA certified and is 8,000% cleaner - not a typo - 8,000% cleaner than gasoline equipped mowers.  John should see longer engine life and reduced fuel costs as well since propane is about 30% less expensive than gasoline or diesel.  The savings are increased with no spillage, theft, or contamination concerns that occur with other fuels.