We would recommend that an external observer watches the initial engine start from a safe distance so that he can identify any problems or faults that may not be visible from the cockpit.


Start the engine in accordance with the aircraft manufacturer’s instructions.

Oil pressure should show on the oil pressure gauge within 10 seconds. On some aircraft it may then take another 30 seconds for the oil pressure to be indicating within the normal operating range due to restrictors in the oil pressure line and the length of the line to the pressure gauge. If the oil pressure is not within its normal operating range with 30 seconds of engine start, shut the engine down and find out why.

Once you have normal oil pressure, run the engine at approximately 1000rpm for one minute.

Check the idle RPM is approximately correct, the idle manifold pressure is approximately 12” – 14” Hg, and both magnetos are working. When shutting the engine down, check the idle mixture. As you move the mixture from full rich to lean, you should see the rpm rise by between 20 – 50 rpm for most engines.

If you have no rev rise or an excessive rev rise, adjust the idle mixture after the engine has been shut down.

With the engine shut down, re-check the engine installation. Pay particular attention for either fuel or oil leaks. Re-check the engine controls and make sure nothing is rubbing against any part of the exhaust system. Make any necessary adjustments such as idle speed and idle mixture.

While you are checking the engine, the residual engine heat will also slightly warm the engine oil.


Start the engine in accordance with the aircraft manufacturer’s instructions.

Aim for a target RPM of approximately 1000 RPM. Allow the engine temperature to warm up until the oil temperature needle is off the bottom peg, around 100°F.

Do a normal but brief run-up checking the magnetos and cycle the propeller.


If you are performing the initial engine start on a Continental engine in a single engine aircraft it is very important that the propeller is cycled so that lubricating oil is supplied to the propeller governor transfer collar. Generally to cycle the propeller increase the RPM to 1600 – 1700 RPM and slowly manipulate the pitch control until you see the RPM decrease by 50 – 100 rpm. If the propeller will not cycle stop the engine immediately and find out why.

With the throttle pulled back, re-check that the idle speed is correctly set. ( Idle RPM should be set to the aircraft manufacturer’s figures ) Slowly pull the mixture out to shut the engine down. If the idle mixture is correct you should see a 25 -50 RPM rev rise. If you have no rev rise it indicates the idle mixture is too lean, if the rev rise is greater than 50RPM the idle mixture is too rich.

With the engine shut down, and the magnetos / ignition system turned off again check the engine and engine installation.

Prior to performing any high power ground runs, cowl the engine, or install a cooling shroud.

Third Start

Start the engine in accordance with the aircraft manufacturer’s instructions. If the engine had cooled down after the second start, allow the engine to warm up and then perform a normal engine run up in accordance with the aircraft / engine manufacturer’s instructions.

Pay particular attention to the ensure the cylinder head and oil temperatures stay within the normal green operating range during these ground runs.

Particular care should be taken with aircraft that do not have, or have only a single channel cylinder head temperature gauge to ensure that all cylinders are remaining below the specified operating limits during ground runs.

Due to the variation between the engine test stand conditions and the engine installation in the aircraft, all engine operating parameters such as idle speed and mixture, oil pressure, fuel flows and pressures, and manifold pressures must be checked and if necessary adjusted at this time.

Follow the aircraft manufacturer’s instructions to check and adjust these parameters to within the specified limits.


Fuel system adjustments are particularly important. Please ensure the idle mixture and speed and the full power fuel flows and pressures are set as specified. It is very important that the take-off fuel flow is not less than the engine manufacturer’s minimum fuel flow for your engine model.

Try to avoid any un-necessary ground running or prolonged idling of the engine as this can cause the glazing of the cylinder bores, ring blow-by and excessive oil consumption.

Please refer to the next section, engine break-in information, for a more detailed explanation of engine break-in procedures.

After the successful completion of the required engine ground runs, make the aircraft ready for its first flight.


Start the engine and perform all normal pre-flight inspections in accordance with the aircraft manufacturer’s instructions.

Plan to conduct the first flight in daylight VFR rules. Do not put yourself under any un-necessary pressure.

Conduct a normal take off. Monitor engine operating parameters. Use cowl flaps and shallow climb angle to keep cylinder head and oil temperatures in their normal operating range.

Fly your aircraft at a suitable altitude. Maintain a cruise power setting of between 65% and 75% for approximately ½ an hour.

On landing, remove the engine cowls and thoroughly inspect the engine and the engine installation.

On the satisfactory completion of the of the engine inspection you can resume normal operation of your aircraft bearing in mind the operating conditions that are need to “break-in” the engine as discussed in the next section.

In addition to the manufacturer’s requirements, we also recommend that the engine oil and oil filter is changed and inspected after approximately 5 hours of operation.

This is also a good opportunity to check the engine installation for any problems.