2 qts
A Troy-Bilt 21 inch cutting blade 190cc 6.7 HP engine does not need an oil and gas mix. It is a 4 cycle engine which keeps the oil and gas separate for maximum efficiency.
64 oz per the manual.
21/2qrts 20w50
14 - 21 ft lb or 19-28.5 Nm
F your site it sucks!
381 gallons of oil divide by 21 gallon containers = 18 full containers which will use 378 gallons of oil. Container 19 will have only 3 gallons in it.
Clean the area around the oil drain tube and dip stick. Remove the plug and the dip stick. Allow time for complete drainage. Re-install the plug and route the hose next to the engine. Fill the crankcase with fresh oil.
You failed to list engine size and make. If it has a horizontal shaft 5−7 h.p. Briggs & Stratton non-Vanguard engine the total oil capacity is 20 ounces. If it is a Vanguard 6 h.p. engine the capacity is 24 ounces. Add 20 ounces and then check the oil level. If it has a Tecumseh engine it can be 20 or 21 ounces. Do not overfill.
Most walkbehinds use 20-21 oz. of oil and riders use between 40-64oz. of oil. Fill carefully to obtain the best performance!
Briggs & Stratton part # 491056 NAPA filter # 1348
twenty eight ounces