"I've heard of that!" and a long thread-hijack....
The "carbon-blasting water" idea had been around for at least over 60 years; and even used one time (at least) while setting a "Time-in-Flight" endurance record; right here in my hometown. "The Longest Flight" (copyright 1998, Bobby Woodhouse and Jim Gillaspe) explained the activity very well; but I don't have my copy at-hand right now; so I'll just paraphrase what I was told by Mr Gillespe:
"About 2/3 the way through the flight; the engine started developing an once-in-a-while 'miss'. (Pilots) Bob (woodhouse) and Woody (Jongeward) figured the plugs were carbon fouling, but they didn't want to end the record attempt just to change plugs; so they talked it over with the guys on the ground and decided to try an old car repair trick. They cut another hole in the firewall and exposed a vacuum port on the Continental (engine) while the ground crew fixed up a big jar with two little pipes in the lid; one pipe just went through the lid, the other went clear down almost to the bottom. They filled the jat with water, and on the refueling run, passed it up to the plane; which they then took up as high as they could go. While Bob drove the plane, Woody hooked a hose from the jar or water to the vacuum port, and the engine stared sucking water. She coughed and sputtered a bunch, but the cool water hitting the plugs blasted the cr*p
right out of the plugs. They did it a couple times, and she ran good for the rest of the flight"
Mr Gillespe passed away in an automobile accident just a week ago today. I had never met the man until the preparations for the 50th Anniversary of the "City of Yuma Endurance Flight". He was instrumental in locating the original Aeronca 15AC (N1156H); helped drive the 28' Ryder van (carrying the Aeronca) from Minnesota to Yuma; helped 'restore' the Aeronca to her "Flight Condition" (there had been lots of mods and a couple of wrecks in the 50 years since the flight); and was the Pilot-in-Command for her post-restoration recertification. I was just the dummy who was then the Yuma Jaycees president at the time and helped fit and polish the aluminum wings. (The Jaycees were the organization the held the first flight). While working on the plane, Jim and I got to know each other; and we found out that we had some strong commonalities because of the Endurance Flight - and not just our first names.
Jim was a 40 yr-old former Naval Aviator who left Oklahoma and "moved West" in the mid 60's; landing in Yuma to find work and build up his cash reserves prior to continuing on to California. In 1959, my Dad -a former Army Air Corps Aviator - sold his dairy farm in New York, packed up his wife and three kids and "moved West"; landing in Yuma to build up their cash reserves prior to continuing on to California. My Mom and Dad found jobs at Yuma Proving Grounds (an Army Testing Facility north of Yuma); and when Mom came up pregnant with a 4th child (ME), they decided to stay, and advanced in their respective jobs at YPG. Dad had started out as a "Control Tower Operator" at YPG's Laguna Field. He ultimately retired having become YPG's "Airspace Officer"; responsible for the enitre YPG reservation from "dirt to 85,000 feet". One of his first duties in that job was to interview prospects for the position of "Control Tower Operator"; he hired Jim Gillespe.
My one and only flight in a small plane was in the "City of Yuma"; with Jim at the controls. He even let me "take the wheel" for a little while - the biggest thrill (after my wedding and the births of our three kids) of my then37 year life.
RIP, Jim. You and Dad can "Show 'em how to fly REAL PLANES with PROPELLORS" together now.