Okay Pe, I ust poped upon the stock carb (WYL) and it has a tappered spring just below the jet. The WYJ does not have this spring. Can you tell me why? While I was at it I swapped the jets out so now I have the bigger jet in the bigger carb. Thanks for all your advise. I had read that someone tried a WT carb on one of these 4-strokes and didn't like the way it worked. Can't control the butterfly to open and close smooth enough.