91fx
 

can a 4s plug be used in a 2s?anyone doing this,what advantages are there by doing it

RE: 91fx
 

I use OS F plugs in YS61, OS55AX, Rossi 61. I find they give a better idle and probably are longer lasting.

RE: 91fx
 

I've used FS plugs in a couple of engines. Near as I could tell, they didn't run any better than with a standard #8. The price of 'em suggests that O.S. started the rumor that they had magic properties.

Now, none of the engines that had the FS plug test sessions had any problems at all and had good needle settings (both needles). They ran great with both plugs.