PROBABLY ABOUT THE SAME AS IT IS FOR A 4 STROKE, MINUS SOME OIL AND A FILTER.
$200 FOR PARTS, $250 - $350 FOR LABOR.
I WOULD HOPE IT WOULD INCLUDE THERMOSTAT(S),COMPRESSION TEST, FUEL PUMP SERVICE, GREASE, PLUGS, WATER PUMP, GEAR LUBE, GEARCASE SEAL TEST IF LUBE IS BAD...