Yamaha F100B F100C Outboards Factory Service Manual, Page 60Get this manual
Periodic checks and adjustments
Checking the valve clearance
NOTE: For checking procedures, see Chapter 5, "Checking the valve clearance"
7Pour the specified amount of the recommended engine oil into the oil filler holeRecommended engine oil: 4-stroke motor oil API: SE, SF, SG, or SH SAE: 10W-30, 10W-40, or 20W-40 Oil quantity: With oil filter replacement: 4.7 (5.0 US qt, 4.1 Imp qt) Without oil filter replacement: 4.5 (4.8 US qt, 4.0 Imp qt) 8Install the oil filler cap and dipstick, and then start the engine and warm it up for minutes9Turn the engine off, and then check the oil level and correct it if necessary
Checking the spark plugs
1Remove the cover2Disconnect the high-tension cords, and then remove the spark plugs3Clean the electrodes with spark plug cleaner or wire brushReplace the spark plug if necessary