150cc 500 series carb problem

[Bryon]

I have a 10T502 1022 b1 10011352 that slows then speeds its engine speed repeatedly almost to the point of stalling. I've degreased all around the carb including the governer springs. They seem to be functioning correctly but I'm not sure. I know ethanol gas was used for awhile so I was wondering if the carb diaphragm might need to be replaced.
Hope some one can help. Thanks Bryon

 

[Boobala]

Sounds like it's "surging" .. meaning a thorough carb cleaning or O/H, I always recommend cleaning the ENTIRE fuel system, meaning an immaculate cleaning of the fuel tank, replace the fuel lines, and filter, and shut-off valve ( if applicable ) .. you dont want a CLEAN carb getting dirty fuel do we ..??