Look on the bottom of the throttle handle for a set screw or opening for one. Sometimes you need to put the throttle into the 2 or 3 o clock position to get to the set screw, thru the opening in the throttle handle.
Failing that, a lot of times the throttle only button can be popped off.
On a side note. Sometimes universal controls are used. If your control is one of those, it may be compatible with Yamaha.
