Engine runs with plug wire off

[Clay R.]

While at an engine show last summer, I came across a guy that could remove the plug wire from a running B&S engine and it would keep on running. The wire was for real because it would give you a shock. How did he do it?
Clay

I saw one setup like that where he had a model gas engine tiny spark plug hidden under the cooling fins for ignition. I am not sure if he had the "real" plug still functioning or not.

- CJ

[Bill Miller]

I found these pictures from a show last fall of a Briggs running on a hot tube.
I thought this was very unusual. I hope they will load . Bill Miller

[Harry]

I knew that I had seen this spark plug story before so I went searching for it. I also found one of the many reasons that this is called the SmokStak - they were blowing smoke and shootin flames!

http://www.smokstak.com/forum/showthread.php?t=2126

[Andrew Mackey]

I have one possible answer to the engine question posted: B&S and some other manufacturers (I know Kohler is one), built engines for the MOPECO Company. MOPECO made propane fueled, engine powered heater-blowers for Public Service, Bell Telephone, N.J. Natural Gas, and other utility companies. The MOPECO Heater-Blowers were used to provide fresh, heated air for use in confined spaces - such as manholes and underground utility vaults. I personally worked on the 3 HP versions, with the B&S and Kohler equipped engines. The engines were propane fueled, and were attached to a squirrel type blower with an 8" diameter discharge that would be attached to a flexible hose that went to the point of use. These engines were equipped with a magneto that had 2 Hi-tension leads, 1 lead went to the spark plug, the other went to the ignition plug for the heater section of the unit. As the engine ran, both the ignition plug, and the engine spark plug would fire simultaniously. Both wires provided enough energy to run the engine. Typically, the B&S unit would throw a 1/2" spark, and the Kohlers were hard pressed to get 3/8" on a good day! If we did not get at least 1/4". then new points and condensers were installed. If that did not work, then the coils were replaced too. (Back then, it was a shop trick to take the heater ignition wire and wire all the stools in the shop together, start the unit, and wait to see who sat on a stool first. You usually heard a yelp when you had a victim sit on a wired stool!) If somebody tried that today, they would probably be arrested! Ahh - to be young again! This type coil was made for 5 or 6 years, in the mid '70s. The wire under the head gasket trick may work for a while, but unfortunately, B&S has changed the gasket material to a Graphite impregnated material, it carries current, and the trick wont work with the new material.
Andrew

I have seen several of these at shows and it is a classic. I saw one last summer that ran without a carberater, a plug wire and the exhaust port was blocked off and yet it purred all day like a sewing machine. After much research and the help from an old timer I figured out the secret. It is somewhat simple but reqiures some engine modifications. I actually felt a little stupid after I figured it out because it was so simple. I swore to the old timer I would not tell and I am going to keep my word, but if you look one over close and use some imagination you will figure it out. BTW the engine is actually running on gas and not "dieseling like I first suspected. I plan on building one of my own when I get the time but mine will have the exhaust pipe plumbed into the air intake and get its spark from a potato. That should blow some minds!

[Mac Leod]

Hello, I have seen a few engines run with out a sparkplug wire...The first was a 2 cycle motercycle...There was a littel too much oil in the gas. It was taken up a very steep hill and then right afterwards parked...no time running to cool down. The air cooled engine continued to run after the killswitch was hit... then the sparkplug wire was removed-what finaly did it was puting the front wheel on a tree and putting it in to gear. The second time was my jaeger...When the govenor came loose the first time and the engine ran over speed (it jumped about 2 inches up when it fired) I pulled the sparkplug wire and it continued to draw fuel, ignite fuel and GAIN SPEED. I cut the fuel of but it still took a minute (seemed like an hour) for it to finally die.

I kinda doubt that the B&S engine you are talking about did what these engines did, but I have seen gas engine run with no spark


Mac Leod