Jump to content

Vote for Tractor of the Month
Garden Tractors and Parts on eBay

- - - - -

Testing for spark

  • Please log in to reply
3 replies to this topic

#1 olds45512 ONLINE  

  • Senior Member
  • Member No: 77943
  • 566 Thanks
  • 325 posts
  • Location: Indiana PA

Posted October 18, 2016 - 10:33 AM

I was told about this the other day from a good friend. He was testing spark on a Kohler and like most people he pulled the plug and put it in the wire and left the plug rest against the head, the plug turned out to be junk but he had a used one that fit and wanted to test it before installing it. Once again with the plug resting against the head he turned the engine over, this time the raw fuel being pushed out the open spark plug hole ignited off the spark plug and caused what he described as a "big ass fire ball". Luckily it went out pretty fast and he was unharmed, makes me glad I use an inline spark tester.
  • Bolens 1000, lyall, boyscout862 and 2 others have said thanks

#2 DougT ONLINE  


    Dog Approved

  • Super Moderator
  • Staff
  • -GTt Supporter-
  • Contributor
  • Member No: 584
  • 5,521 Thanks
  • 4,177 posts
  • Location: north central Ohio

Posted October 18, 2016 - 10:46 AM

He must have had the engine pretty flooded to do that. I've been known to hold a lighter to the plug hole and turn the enine to suck the flame in. If they are flooded they dry out quick. I've had some good poofs but nothing I'd describe as a big fire ball. Must have had quite a bit of gas to do that.

  • HDWildBill and boyscout862 have said thanks

#3 Mark 149 J. OFFLINE  

Mark 149 J.

    Mark J.

  • Senior Member
  • -GTt Supporter-
  • Member No: 78623
  • 480 Thanks
  • 328 posts
  • Location: Kennewick, Washington

Posted October 18, 2016 - 10:50 AM

In an automotive class, a group of students removed all of the spark plugs on a fwd. 4 cylinder dodge.  They didn't disconnect the coil and cranked the engine over.  The gas shot out of the spark plug hole covering the wall with gas.  The spark plug wire ignited all of the fuel setting the wall on fire.  It was concrete block but the paint was burning.  Someone grabbed  the fire extinguisher to put it out.  The instructor wasn't to happy but after a bit we all laughed about and learned an important less.

Edited by Mark 149 J., October 18, 2016 - 09:41 PM.

  • Alc, Bruce Dorsi, HDWildBill and 1 other said thanks

#4 EricFromPa OFFLINE  



  • Senior Member
  • Contributor
  • Member No: 2135
  • 2,169 Thanks
  • 2,250 posts
  • Location: Bedford County Pa.

Posted October 18, 2016 - 06:46 PM

My dumb butt pulled the plug on a OHV briggs engine that the carb had filled the crankcase with gas.Pulled the plug and cranked it over and stepped back and watched it burn.


Whole engine went up in flames.Block had a couple quarts of gas in it.Good thing I bought it very Cheap for the engine.



That was about 10 years ago.I'll never crank one over again to blow the gas out of the cylinder With the plug still in the lead and key turned On.I jump the solenoid over with the key OFF and Out of the tractor and No Spark plug hooked to the wire.Much safer but still a little risky.

  • Alc and Mark 149 J. have said thanks