The 26cc 4stroke engine puts out about 1 horsepower. I am expecting the engine to have less power running on HHO so i think i will limit my projects to 1/2hp. The real question is what to run with the engine. Some ideas i have for the motor are...

- Water pump. Could be very useful when gasoline is hard to find. When gasoline is in short supply to run a pump the small HHO engine could do the work. The HHO generator battery can be charged with a solar panel to store power so the generator can run the pump at night.

-Motorcycle/Scooter/Bike
On my YouTube channel i made a 2 stroke gas powered bike with a chainsaw engine of a similar engine displacement. I hear that the 4 stroke engines produce really good torque, run way cleaner, and have a better overall life expectancy than a 2 stroke. It may not be the fastest thing on the road but a small scooter with a large storage capacity battery could generate all the fuel it needs onboard and on demand. Every time the bike is parked the battery could be quickly charged with a high amp battery charger or with a solar panel. A bike shed could also be sold with this product to keep the scooter dry/clean and the shed roof could generate solar power for the scooters storage battery. This would make it ready to ride anytime.

- Run small mechanical items like farm or mining equipment.
There are various small engines on different farm, yard, and garden equipment. Any of these engines could be easily converted to run on HHO. These engines although getting better in technology still put out a large amount of pollution. Running these machines on HHO would help produce less emissions from the farm or garden.

-Clean Idle device.
If enough HHO could be produced safely to run a production car engine at idle it could be used instead of gasoline while the vehicle is idling. If the car's battery storage capacity is enlarged the vehicle could charge the battery bank up while driving with the HHO generator off. When the car is idling at a light or in traffic the fuel injectors could be shut off and HHO could be used to idle the vehicle.
If the battery bank is charged to 100% the HHO generator could provide additional fuel savings by adding HHO to the engine off the excess battery power while highway driving. If vehicles could idle on pure HHO pollution in cities would be greatly reduced during rush hour times and making the air overall cleaner. The power for the HHO generation is made when the engine is running on gasoline and has power to spare.

After i get the full scale prototype (mine is currently 1/5th scale) i will be able to test a few of these ideas in a real world applications. The clean idle device is something i am going to seriously look into. Basically it is taking wasted power and using it when you usually waste power. Could boost most vehicle's fuel economy by 20 or 30 percent.