Running Too Rich

[bmetras]

Hello all, first post, new member ..forgive me if this has been covered elsewhere on the site.

Just picked up a 2007 Roketa Sicily 150 cheap.. was advertised as "engine runs well", which it did at idle and off idle, before loading it onto a carrier.. once I got it off the streets of San Francisco and home for a test ride, I found that anything approaching 1/2 throttle the engine would bog terribly (30mph maybe max), release the throttle, smooth running and idling up to about 1/2 throttle, then bog to the point of killing the engine..

This morning I removed the air filter (clean enough) same problem.. removed the bodywork to get access to the carb ...removed the snorkel from the mouth of the carb, and the engine ran really well on the center stand.. took it out for a test and it easily ran over 50mph.. hooked the snorkel back up and the same poor running issue came instantly back.. checked for obstruction in the air intake and it was clear.. the engine idles nicely hot or cold.. when cold, there seems to be a high idle circuit that works, and then it drops down to normal idle after it warms up..

So my question is if there is anything from the tank to the carb that could cause a severe, overly rich condition that would be masked by letting the carb breathe freely without the air/snorkel intake system in place..

Thanks for any insights or further things to test..

Bruce