I HAVE RECENTLY PURCHED A SECOND HAND BOAT BY PRIVATE SALE FITTED WITH A 140 EVINRUDE, WHEN WE TOOK IT FOR A TEST RUN IT SEEMED TO RUN WELL EXCEPT FOR COLD IDLE, I HAVE SINCE HAD THE MOTOR SERVICED AND IT RUNS EVEN BETTER BUT HAS SLIGHT SURGING BETWEEN 3500-4000 RPM THE BOAT HAS BEEN SITTING UNUSED FOR MAYBE A YEAR OR MORE. I DIDNT NOTICE THE SURGING DURING THE TEST RUN,BUT WE DIDNT REALY RUN MUCH AT THIS REV RANGE. IT REVED OUT TO 5500 RPM OK DURING TEST AND STILL DOES, IT JUST SEEMS TO BE THAT SMALL BAND OF RPM. I WAS WONDERING IF THE LACK OF USE WOULD HAVE ANYTHING TO DO WITH IT AND ALSO IF THERE IS ANY FUEL TREATMENTS THAT ARE WORTH USING/TRYING. THERE IS PROBABLY STILL SOME OLD FUEL IN THE TANK AS WELL. VRO IS STILL IN USE (DECSION STILL PENDING ON THAT ONE)THAT HAS OLD OIL AS WELL. I WAS TOLD THAT THE MOTOR IS A 1986 MODEL, THE SERIAL #A0309435. I AM LIVING IN NEWCASTLE AUSTRALIA. THANKS FOR ANY SUGGESTIONS