Engine Surging

[Mike G]

My Skorpion sport has started surging when the rpm goes above 3500. It feels like the brakes are going partially on and off in about a 1 to 2 second cycle but it is linked to engine speed not road speed. It does it when the throttle is open or closed. I am mystified as to a cause. The only things that come to mind are 1. the CV carbureter is bouncing open and closed slightly or 2. the balance shaft keyway is loose and resonating some how. It does not feel electrical as it is not sudden like a misfire. I shall investigate, starting with the carburters but any ideas would be gratefully received.

Mike

[basser23]

I'd be running some Seafoam with the gas to clean it out first,youd be surprise how good that stuff works!
Sounds like its going lean on you...

[edfmaniac]

Seafoam first. Then pull the carbs and clean them manually if the chemicals don't work.