A fuel dot should not cause any problems . That is why I use them over the "easy fueler". You may however have a fuel line/air leak problem somewhere else in the sytem. If a new plug doesn't cure it check all your fuel ines for the slightest pinhloe or crack. Even poor routing or improper fuel line lengths can cause this type of problem too. Make sure none of them are too short causing a sharp angle to the nipple as this will lean it out like a pinched line would. Too long of a fuel line can also cause a problem if it's extra length causes a bow in the fuel line creating an uphill battle for the fuel to draw through. I spend a frustrating afternoon finding these things out myself. After re-doing all the fuel lines at correct lengths with no binds or steep uphill routes, it finally ran just right again. Personally I find my OS 46 size engines like a hotter plug than the 5. I use OS#8 plugs with good success. Good luck.