the y plug runs hotter,therefore the fuel oil mix burns cleaner.the other plug will be cold and not ignite the mix as well use what is recomended by the manufacturer.make sure the carb.is set properly.

What kenny said. "Y" means extended tip for wider heat range.

fouling/oil build up.

If you compare the two next to each other, it does not have the extended ceramic tip. It will work and run, but it will have a greater chance of fouling/oil build up.

Well as long as they are same diameter AND length fron thread to end why not?

also, will it damage my motor to use it?