The engine operating limitations are listed in section 2 of the Flight manual at table 2-4. These limitations are extremely important and should be memorised prior to operating the aeroplane engines.
Engine limitations table 2-4 from the Aircraft Flight Manual
Engine oil limitations are important to the Conquest engines as different types of oils should not be mixed. Never operate the engines of the Conquest when the oil level is below the ADD mark on the dipstick prior to engine start. The best time to check the oil level being after an engine start.
If during a preflight inspection the oil level is found to be abnormally low, it is possible that the unfeathering pump switch may have been activated causing oil to be transferred to the gearbox. If this is the case the oil level can be restored to normal in the oil sump by simply motoring the engine with the STARTER MOTOR switch located on the left hand switch panel fro 5-10 seconds.
After motoring the engine on the STARTER MOTOR switch recheck the oil level and if required top up the oil level using the same engine oil type and brand that has previously been used on the engine.
Remember -- IF IN DOUBT... ASK!!