20 inch give or take an inch i guess....
just got back from my 20 hour service... this is what the paperwork lists was done
changed oil and filter
changed lower unit oil
inspected: water pump; spark plugs; propeller and shaft; throttle control; shifter control; trim; all transom bolts and nuts
tested unit with water muffs and rechecked oil
ALL O.K.
$131.05 parts and labor