I went to change the spark plugs in the GST the other night only to find that I could not remove them becasue the bolt is much larger than on a normal plug. Tried all of my deep well sockets and none would fit any idea on the size of these bolts. I was un-aware that they used various sizes for plug bolts.
#7584, "RE: Odd sized sparkplug bolts ???" In response to Reply # 0
You need a 13/16, thin wall socket to remove the spark plugs. This is a different size then what is used for the 420a engine. So yes, various sizes are used.
