Get a Fox Idle Bar plug if you use an engine witha long plug (OS 46FX and the like) I switched from the OS 8 plug to these and so far I havn't had any trouble at all! As a matter of fact, the engine runs a little better!. Then again, I replaced both of my 46FX's pistons & liners with Chrome ones from Magnum (pretty much a direct fit) and they work great! Good Luck!

Don