Modern Vespa

I have a 150 super that won't run without the choke out and a constant flow of gas. I've cleaned the carb and replaced gaskets. Trying to figure out why it won't run without giving it constant gas 😏. I'm a "you tube mechanic". So trying to trouble shoot.

From what I've read it seams that I may have an air leak somewhere.

I was hoping the pros in here could help. I noticed that the rubber seal that lines the air box does not go all the way around...could that be he issue? I was told by a real meachanic that it was ok that way but that doesn't make sense to me.

Help! and Thanks![/img]

Check your idle jet first. If you cleaned the carb, you may have already done this. For reference, it is the smaller of the 2 you would have removed. Big one is the main jet stack, which is made up of 3 pieces and the smaller idle jet. It has a very small jet to clean, shoot some carb cleaner thru it with the straw that comes with the cleaner. shoot some cleaner down the receiving area where the jet lives. If these are both open and clean, and the carb body is not warped with a nice sealed fit, then you probably will need to look for a leak.

Thanks. I'll give that a try

Also likely that one or both of the cranks seals have failed. When was the engine last resealed? Ethanol laced fuel will kill the crankshaft seals, especially if you do not turn the fuel off before parking the scooter. Leave the fuel tap on, flood the crankcase, and the seals will basically fall apart.

The drill (once you replace the seals) is fuel off, idle engine until it stalls, park scooter.

Pro tip: To restart from a dry float bowl; turn fuel on, lean scooter to the right for 30 seconds to "overfill" the float chamber, pull choke and kick. It should start on the first or second kick if everything else is in good shape.

Reset or replace your points first before you go splitting the cases for seals.Wrongly set points gap will give you those symptoms you posted.