Chainsaw Suprise

andy fineran

Member
Messages
25
On a hot summer day I had pulled the rope on my chain saw 15 or so times. Never one time did it try to start. This is normally a 3 pull saw at 20 degrees. So I stepped in the garage to get out of the sun. Put the saw on the workbench and removed the spark plug.
I reconnected the plug and wedged it in the handle grip to establish a good ground, and somewhat slowly pulled the rope to see if I had a spark. I have done this a hundred times, and I am sure many of you have too. I had no more pulled the rope 4 inches when the spark lit the fuel mist pumped out of the spark plug hole by the piston. The exterior of the saw must have had a film on it that burst in to flames, as did several spots on my table top. (Used for mechanical things or cleaning, not my woodworking bench). The fuel was consumed in seconds. The other flames were snuffed with a hand full of rags, and nothing else lit. The whole thing was over in 6 seconds only because I had lids on stuff and some luck. Mostly because it happened in a dark garage with my face a foot from the plug, it did manage to have a negative impact on my choice of words. In the end. I had confirmed good spark, good fuel, oxygen and the cylinder was certainly no longer flooded. The plug went back in and it it started on the second pull. Better to be lucky than good?
Again, I have done this a hundred times, on many engines and never thought of the mist expelled from the plug hole. I do think this was assisted by the summer heat.

Saw in the winter. Sit on the porch in the summer. Much safer.
 

Leo Voisine

Member
Messages
5,071
Location
East Freeetown, Massachusetts
Summer heat for sure helped that happen.

I have seen on a few occasions where gas ignited due to any number of reasons.

It does happen and it is not at all unusual.

Glad that you have been so lucky so many times, but don't count on continued luck.

One such occasions I know of blew up and demolished a 30 foot boat. The guy aboard severely burned, almost died.
 

fred hargis

Member
Messages
1,245
Location
Wapakoneta, OH
I've done that myself many times with small gasoline engines, I'll be more careful from now on. Glad you weren't injured or burnt. Thanks for sharing.
 

Dave Hoskins

Member
Messages
4,770
Location
Parker County, Texas
Lucky, indeed. Flash fire is always a concern in a shop, I think. Due to the poor gas we get now and with it fouling plugs more often than back in the day I keep a stock of spark plugs around. When my saws begin the "hard to start routine", I just change the plug. I don't even give it a thought. My saws get a lot of use. But, one thing I started doing quite a while back is when I but the spark plug I blow the cylinder out with the air compressor. When I started doing that it's not because I was thinking about fire. I just figgered if the saw was flooded and fouled the plug, just go on and blow it out while changing the plug and everything would be fine and dandy. Never had a spark problem with these Stihls. Had an old AV10 that was about 20 years old I think. Finally crapped out due to lack of compression. Still had spark though. Not that it did it any good with no compression. Poor thing. Guess I should have given it a proper burial. :D
 

Mark E Smith

Member
Messages
190
Location
Arkansas
lol...your solution to check for spark was much safer then mine...years ago I had a lawn mower doing much the same thing (back in the pull start days) any ways I did the same thing, pulled the plug, it looked fine but I wasn't sure if was getting spark...so I jammed a screw driver into the spark plug wire cap, called my wife over, I handed the screw driver/wire setup to her and said hang onto this for second...lol...well you know where this going...gave the pull start a tug...wife yelled..dropped everything and started cussing me..well guess I got spark. She didn't talk to me for several days without calling me a very rude name, even a few compound cuss words...got real hungry over the next few days too, I was a little worried about anything she might feed me. So I think maybe your solution and outcome would have been better, no fire like yours, but I got burned trust me...lol...
 
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