Motorcycle Conversion
After the Motorcycle, our 2nd conversion was the Honda lawnmower. The lawnmower conversion was nearly the same conversion as on the motorcycle, but this time we learned that carburetors are not necessary. So we ditched the carburetor and put a pipe threaded into the intake. We’ll come back to this in a minute, lets talk about how we get to fuel delivery to the engine.
We used a small .13 cubic foot tank (STP). To minimize vibration the tank was mounted to the handlebars. An AHA volunteer fabricated a steel case that housed the H2 tank. We then installed a two stage H2 regulator (which should actually be 2 separate regulators) to step down the pressure from 2,200 psi. down to ~10psi. from there we ran a ¼ inch stainless steel line to a check valve, a few inches downstream of the check valve another ball valve was installed. The function of this ball valve was to allow the lawnmower operator to meter the fuel from low idle to high idle. With hydrogen you want to meter the fuel not the air (unthrottled air). With the ball valve we drilled a hole in the handle and hooked it to a spring that is controlled by the normal mower throttle linkage. Downstream of the modified ball valve (H2 metering valve) we installed a ¼ inch stainless steel line vibration loop. Vibration loops are very important for the integrity and safety of H2 fuel lines. If a fuel line experiences stress the vibration loop should help relieve the stress and prevent a stainless steel line from snapping. The stainless steel line was run to the opening of the intake valve. We then positioned the tubing behind the intake valve with the end pinched to help create a high pressure H2 jet flow into the combustion chamber.
After we converted the lawnmower we took it around and showboated our new and greatest achievement for the time. We felt it was a great achievement because it demonstrated the economic feasibility of H2 engines. We started up a business to help fund our organization called Clean Air Land Care CALC or what is now known as H2Mow in 2000. We are still taking orders and providing land care options with our hydrogen products to this day.
Since the original conversion from gasoline to H2 we have put over 100 hrs on the engine the lawnmower still runs however we have improved our conversion skills and are using certified natural gas kits which have proven to be safer in regards to flashback. The biggest lesson learned from the Honda engine conversion was that if your lawnmower starts to flame up (because of fuel flooding the chamber and in our case catching excess on fire) immediately go to the valve and close it. The moral is shut off the supply of h2 fuel before killing your engine and use a flashback arrestor. This applies to all h2 conversions big and small.