Its easier to make a short reach plug work well in most applications than it is to get people to use the correct plug in a .10 or .15. Why are people so obsessed with glow plugs? Is there that much difference between them? Can anyone listen to an engine and tell what plug is in it? Why does a high end mfg. like Jett recommend cheap K&B plugs. After reading these posts it appears that an engine simply will not run without an OS F plug.