YS 63 Problem
 

I have a new YS 63 that I was bench running. A total of 26 oz through the engine. It was running fine with nice thick smoke and bang. The engine stopped. I finally got the engine restarted but the throttle body no longer controls the engine speed. 1/2 throttle runs, full throttle runs, close throttle the engine speeds up. Move throttle arm to idle and the engine will drop of speed. There is no transition. It seems to be either on or off.

Never had a problem like this with any of my YS engines.

How should I approach this problem?

RE: YS 63 Problem
 

Did the cap screw holding the throttle arm on come loose???

RE: YS 63 Problem
 

Nope ... the cap screw is still nice and snug.

RE: YS 63 Problem
 

Not sure where to look. Sounds almost like it backfired and damaged something perhaps a trip to YS Parts and Service will do it good.

My inital thought was the throttle barrel stop screw....This would cause the throttle barrel to leak and could give it some symptom like you are describing....but if this screw is still in place maybe there is some dirt or debris in the throttle barrel, fuel control slot or what we call the scroll. A piece of crap could be blocking this slot partially....when it at full power the dirt is out of the way but as it transitions back the debris is stuck in the slot or may attached to it somehow.


Troy Newman
Team YS

RE: YS 63 Problem
 

Thanks Troy. I believed it backfired. The engine has been sent to YS Parts and Service.