Sparkplug failure

[Rusty McNeil]

Nothing to do with the Vmax...

My Yamaha Pro-hauler which is less than a year old and has maybe 20 hours on it suddenly quit running when I was out taking my dog for a ride around the nieghborhood today......
The Pro-hauler is basically a glorified Yamaha golfcart /utility vehicle with a Yamaha 4 stroke 360cc industrial type engine in it......
It had fire and it had gas....
I pulled the plug and no fouling or pitting..looked perfect..
Pulled the carb figuring crap gas and lack of use..(the gas was from LAST deer season)
I cleaned up the carb and re-assembled everything...
When I was re-installing the plug I noticed the porcelain cone sliding up and down the electrode from the normal position out to where it would touch the ground electrode.....

It was broken cleanly up inside the plug....allowing the spark to go to ground up inside the shrouded part of the plug.
There were no sign of overheating or detonation (we're talking about a lawnmower engine here, right?)

Has anyone ever seen a plug fail in this manner?
I never have.

I replaced it and it runs fine...it was an NGK by the way..

Rusty

 

[mikemax04]

Rusty, any chance you can take a picture of the busted plug for us to see?

 

[Rusty McNeil]

Hey I'm on vacation this week so I might actually get time to do some of the pics that have been requested in the past...

The sparkplug...
the air horns...
the wideband air fuel o2 datalogger with guage and shiftlight ......
The relocated tailight....

any other mods I can think of.....

Later


Rusty

 

[Rusty McNeil]

I'm on vacation so I may actually have time to get pictures of some things that have been requested in the past....as well as the plug


air horn setup
Gutted muffler cans
Wideband air fuel datalogger and display...