Modern Vespa

Hey guys, I have a 68 Sprint 150cc and the other day I had to stop a few times on the way home because at top end speed in 4th gear it started to bog a little then just shut down. I checked the gas lid on the tank to make sure it wasn't on too tight. I loosed it up a bit then after a few kicks it started up again. This morning on the way to work it did fine till it did it again. I heard like a little "sput" sound then just started to die on me.

I was wondering what the hell it could be? It's acting like it's starving of gas at top speeds? Am I getting enough spark? I'm thinking on changing out the spark plug to see if that helps any. If anyone out there has any suggestions or thoughts it would greatly be appreciated.

Thanks!

I highly highly doubt it's the spark. When was the last time you had the float bowl open? I suspect you may have some moisture adulterating the float bowl, and bogging the engine down when wide open, or your jet's a bit dirty.

I've had to open it recently and the float was working good. Gas would enter and the float would rise (not taking in gas and sinking). I think the carb is somehow flooding at top end and that's why it's stalling out?

Ok..I think I get it...I should try and check the main jet to make sure it's not clogged. Does anyone have any tips on how to properly clean the main jet? Thanks -