Continental make two “styles” starter adapters for their engines. The “old style” starter adapter has the clutch spring contained within a sleeve, and the “new style” starter adapter has the clutch spring exposed on the shaftgear.
Due to the design differences between the “old style” and “new style” adapters, the “new style” adapters will not allow the engine to be turned backwards. Trying to turn an engine backwards that has been fitted with a “new style” adapter will damage the adapter and or the engine.
When installing the starter adapter perform the following tests to check that the starter adapter and starter motor are working correctly.
Firstly before installing the starter adapter check that the starter adapter will release correctly.
Secure the main gear shaft in a soft jaw vice. Using a large flat blade screw driver wind the worm gear shaft counter-clockwise. ( Clockwise for LTSIO engines. There is usually an arrow stamped on the housing showing the direction of rotation of the starter motor.)You should feel the clutch spring grip the shaftgear and turn the adapter. Next release the screw driver. The adapter must unwind smoothly and completely release the shaftgear. The “old style”adapter should turn freely in both directions around the shaftgear while “new style” adapters will only turn in the normal direction of rotation . If the adapter does not fully release the shaftgear do not install the adapter on the engine.
Repeat the above test after the adapter has been installed on the engine. Again the adapter should smoothly and completely release. If the starter adapter does not fully release after it has been installed on the engine, then there may be a misalignment problem due to a bad pilot bearing or poor crankcase overhaul.
If you are fitting an “old style” starter adapter to the engine, the starter motor must allow the adapter to unwind otherwise the clutch spring will drag on the shaftgear causing premature wear, and or catastrophic failure of the adapter.
Check the starter motor will turn freely. You should be able to turn the starter motor in both directions with your fingers. If the starter motor does not turn freely, the starter adapter may not fully release. A stiff starter motor that will not let the adapter fully release will at best lead to premature wear, and possibly the catastrophic failure of the clutch spring and adapter. We recommend that the starter motor is serviced or overhauled whenever the starter adapter is changed.
Some of the new style starter motors with permanent magnets and or gear reductions should not be used with the “old style” starter adapters as they do not allow the starter adapter to reliably release.
The fit of the starter motor to the adapter must also be carefully checked. In particular check that the drive tang of the starter motor does not bottom out against the adapter. If the starter motor drive tang does bottom out in the adapter, then the starter adapter will not release causing the problems listed above.
Finally, briefly attempt to start the engine. Crank the engine with the magnetos switched off. After the attempted start, check that the starter adapter has fully released.
BE VERY CAREFUL BEFORE MOVING THE PROPELLER. CHECK THAT THE MAGNETOS ARE GROUNDED (OFF) AND KEEP CLEAR OF THE PROPELLER ARC BEFORE MOVING THE PROPELLER IN EITHER DIRECTION.
With an “old style” starter adapter fitted, the propeller should turn freely in both directions.
If the engine does not turn freely the clutch spring has not fully released the shaftgear. Do not operate an engine where the starter adapter is not fully releasing as this can cause premature wear, and possibly the catastrophic failure of the clutch spring and starter adapter and subsequent damage to the engine.
When a “new style” starter adapter is fitted to an engine, the engine will only turn freely in the normal direction of propeller rotation. Do not turn the propeller backwards on engines that have the “new style” starter adapter fitted as, doing so will damage a “new style” starter adapter.