Hello fellow builders and tinkerers! I got a small 26cc 4 stroke weed eater engine a while ago and decided to tinker. The carb was completely shot and the cost of replacing it would not be worth it (but yay free junk!). Since i have seen many videos of people running small engines on propane and alternative fuels it thought i should give that a try.
Step 1: Propane Conversion.
Since the carb was broken i removed and sealed off all unnecessary parts. Then i blocked off any tiny holes that may leak air into the carburetor with silicone sealant. The choke on this engine is built into the air filter housing so i put it back on to regulate the amount of fresh air going into the engine.
Using a basketball pump from the dollar store i used the needle and hose to deliver gas to the carb. Drilling a small hole into the body of the carb i glued the needle into the housing. The needle had a few millimeters cut off the end to make it fit into the center of the carb.
This is where i left off on converting it to propane. I am currently waiting on parts. A propane camp stove will provide me the bottle hookup, safety valves, and the flame control for the burners can make a "throttle" valve for the engine. This will be covered in a future instructable.
Step 2: How About HHO? Run the Engine on WATER!
Run the engine on water? SURE!
I learned that you can split water H2O into HHO using an electrolyte and some electricity, Fun! A fuel with its own air source. What can go wrong. After some Googling and YouTubing I decided to build a small HHO generator with large stainless washers and a Mason jar. Surprisingly simple to do!
Step 3: The Success and Fail. Also a Huge BANG!
After some experimenting with the mini HHO generator i realized i will not create enough gas to continuously run the engine. This can be upgraded at a later time. Using a balloon hooked to the HHO generator i created some fuel storage. Using the balloon i went outside and gave the engine a try. Hopefully the basketball needle and the pressure in the balloon is enough to provide gas to run the engine. AND IT DID!
Examination of the fail.
I talk about something i called a "saftey preventer" which sounds like something that would make your project more dangerous LOL. What i was trying to say is i need flashback protection. Hydrogen by itself is crazy flammable but with oxygen mixed in with it is dangerous. The pressure was not high enough in the balloon on the 2nd start and the ignition timing was set too early (set for gasoline) so when the engine spun the spark plug fired while the intake valve was still a tiny bit open. This cause the carburetor to backfire sending a flame up the fuel line to the balloon and BOOM!
Step 4: Lessons Learned and More Improvement.
Did you know that a 4in balloon of HHO has ignites with the sound of a cannon? I almost pooped myself.
I will continue abusing this engine and doing crazy projects with it. Before i look into making this run on HHO i need to address a few of these issues.
-- Flashback prevention. The easiest way to fix this problem is to remove all open space possible in the fueling system with water. This will only keep a very small amount of gas outside of the motor in a vented container. If the system backfires it will be very small.
-- Cooling system.The water mixture in the cells gets warm while the reaction process is running. Using an external tank and/or radiator can increase water storage and keep the system full eliminating hydrogen bubbles in the fueling system.
-- Charging system. HHO generation takes a lot of power to make. Using a small generator on the engine would help keep the battery charged longer but i think the battery will still need charging between short uses. A mixture of a generator and a solar panel may help produce a longer run time.
-- Dual fuel setup.A quick change fitting and some way to adjust ignition timing a few degrees with the flip of a switch would be perfect for a dual fuel setup.
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