Hi Alan - I'm thinking now that your engine is painted black...in which case the oil level is correct when you take out the 2 pronged filler plug and add oil until it starts to run back out - making sure the machine is level, of course.
As for the throttle linkage, the fault must be in the control lever on the handlebar....maybe something has broken in here? Trouble is, I cant for the life of me remember what the thing looks like - sorry!
John
June 2009