Having just got the house, the lawn here is tough as nails, I tried to do the healthy green thing, I tried to mow it with a neighbors push mower, but stopped every 6 inches with fouled blades. Then I used an electric weed wacker making the yard look blotchy, next I borrowed a neighbors electric mower, same thing, the blades slammed to a halt. So the local kid looking for work mowing lawns hit me up, I told him go for it. In 45 minutes he had the front and back mowed.
I was impressed with the power of the ICE mower, but realizing the fuel burn of such a primitive work based engine, I sat down and started looking for alt fuel mower conversions. I haven't found a thing on the web, but I dug up one of my old Popular Mechanics from the 70's and it said breifly how to convert lawn mowers over to alcohol, just run it with the choke on and the mixure needle at full rich. If it fouls out, ease up on the choke.
So now Im looking for a used lawn mower to experiment on.
Also, I used the Bowling and Grippo header calculator at (www.bgsoflex.com/bestheader.html) and found the exhaust length of a 125 cc or 7.65 cubic inch Briggs and Stratton, with 1/2 inch exhaust opening, and a running speed of 3400 rpm to have a best tuned header length of 17.88 inches.
sharpen the blade on the electric mower and give it another try, our electric mower can mow weeds the size of a pencel without much truble if the blade is sharp, the battery is on it's 3rd year and is going strong and will only cost $35 to replace, or about 10 gallons of gas, and that would be enough to run the gas mower for a single summer.