YT3600 Crazy high rpm's

[Bigfish8432]

I have a YT3600 that's been sitting for 3 years.  I changed the battery, spark plug and Oil.  It fired right up but when I throttled it up the Rpm's  went crazy high.  I can't figure out for the life of me why.  I've tweaked it with still no luck.  When I turn on the mower... I have to throttle it up more... then when I turn off the mower it jumps back up again!  Does anyone have any experience with this?  Anything will help!
Thanks

[valdez]

My first suggestion is to disassemble the carb and clean it carefully.   The throttle slide needle might be loose and moving on its own, jets could be gummed up, the float might be stuck opened, etc..   After you prove that the carb is OK, then look at the governor.