My lawnmower shot out the sparkplug.replaced it, same thing happened. gets hot, then shoots out 7 ft. help?!?

Question

this last time it ran for about 10 minutes (on a brand new plug) before shooting out. mower is 6 years old, runs great until this.

Answer 1

this is  really odd . Are you sure you have the correct spark plug for that engine??? I have never had this happen to me or anyone i know.

I think there is a Briggs and Stratton site whre you can get some info,,,,if that is what your engine is. The only other brand i am familiar with is Tecumseh.

I see that you dont use email so getting help here would be difficult. Maybe you should take it to a small engine repair shop and have them look at it.

Answer 2

Sounds like your spark plug hole has lost its threads.  As a small engine repair if it can be Heli Coiled.

Answer 3

If someone screwed the plug in MUCH TOO TIGHT, several times, they may have reined the threads.

If that is the case, the plug can not really remain in the hole, under the great pressure the internal combustion engine creates.

This is the only thing I can think of.  I have NEVER heard of a "Spark Plug Cannon" like yours . . . ?  Gotta be the bad threads!

Answer 4

Your problem is not uncommon at all.  For whatever reason the threads in the engine head are almost gone.  When the engine heats up the spark plug hole expands and......

If you are the handy type there is a kit you can buy that includes a tap for cutting new over sized threads and a sleeve that fits your spark plug to s***w into the new threads.  It is do-it-yourself friendly and is  easier and much less expensive than a Heli-coil kit which is very expensive and requires a bit more skill.  Check with your garden equipment dealer or auto parts store.