The Kickback Protection System or KPS® for the NL and NL/EC family of starters is through a field-replaceable shear pin. When energizing the starter, if the pinion engages the flywheel and the starter motor spins (or at least sounds like it is spinning), but the starter’s pinion gear does not rotate you should replace the shear pin.

This condition is related to the starter drive extension and retraction and affects all styles of starters. If, during normal extension, the gear does not extend completely, stress will be placed on the drive gear. If the starter drive does not disengage after start, the engine will tend to drive the gear placing stress on the gear and destroying the motor. In either case, the gear will rapidly wear or fracture.

In some cases, engine kickback will fracture starter drive gears. Kickback is related to engine set up and can be anything from incorrect timing to problems with the fuel system. If kickback is noticed as a common occurrence on the airplane, diagnose and repair the problem or the replaced starter drive may fracture again. Many of Sky-tec's current starters offer kickback protection.

Use a Lycoming alternator strap and MS20074-05-06 (5/16-18 thread) bolts. 

For Continental engines, the most likely cause is a slipping starter adapter. This requires replacement or overhaul of the starter adapter.

There are two potential causes of this condition. If it is a mechanical starter drive (Bendix) and sticks intermittently, it most likely needs to be lubricated. This type of starter drive is initially lubricated to allow smooth operation. The drive gear must move in and out and also rotate. In use it can become dry and may begin to stick and fail to engage or disengage. We recommend lubricating this type of starter drive every fifty (50) hours of operation.

The other likely factor for intermittent engagement would be a faulty starter contactor. If you want to check a contactor, it is best to do so with a load applied. Resistance in the contactor, even a fraction of an ohm, is enough to produce poor or no operation due to the high current field. In a 12-volt starting circuit drawing 60 amps, for example, the addition of 0.2 ohms of resistance due to an oxidized connector or carbonized contact may drop the current to the load to 36 amps. This is a 40-percent loss in starter operating power caused only by a 0.2-ohm resistance.

Checking the circuit without a load would require that a lot of resistance be placed in line. The best method of checking the contactor is to disconnect the lead from the starter and connect it to a battery load-meter tester. Activate the contactor and check the voltage on each side of the contactor. A 0.1-volt drop is normal for a new or nearly new contactor. If you find any more than 0.3-volt drop, replace it.

THIS CAN BE A DANGEROUS SITUATION. The starter contactors in many older aircraft may become welded shut after years of use. BE EXTREMELY CAREFUL. A starter contactor that is welded shut could cause the propeller to rotate when the master switch is energized, regardless of the position of the start button or switch. Replace the starter contactor. Your starter may have been damaged by this as well and may also need to be overhauled or replaced.

It appears that Superior reverse engineered the 60882-type ring gear support assembly (for 122-tooth ring gears) when they manufactured and PMA certified Superior Ring Gear Support Assembly PN SL77579-1 Rev.11 (for 149-tooth ring gears). Unfortunately, when pairing those ring gear support assemblies with 149-tooth ring gears, the ring gear rests further aft than Lycoming specification and therefore tends to crash the front face of NL-type starters by a mere couple thousandths of an inch. Other starter models tend to stand back sufficiently from the ring gear, so the mismatch is not as problematic. Since the NL “hugs the line” defined by Lycoming, the mismatched ring gear and support assembly causes an interference condition.

Lightweight starters do not have as much housing bulk surrounding them, so they aren’t as effective at insulating the gear train noise from the operator. To compound the issue, switching from a legacy heavyweight starter to a lightweight starter may also change the design style from a direct drive to a gear reduction drive in order to obtain the same drive torque. Gear-reduced starters have a much different noise signature than direct drive starters.

First, the firing end of the plug must be cleaned of lead, carbon and oil. Once cleaned you can use the Tempest AT5K® or a multi-meter. If using an AT5K please see the tool section of our website. If using a multi-meter place one lead on the center electrode and the second lead on the contact point inside the spark plug terminal well. Be sure that your multi-meter is set to the correct setting.

Yes, you should rotate your spark plugs every 100 hours. This will help even out electrode wear caused by constant polarity and capacitance after-fire. Place them in a Tempest spark plug tray (P/N T240) and follow the rotation guide supplied on every Tempest spark plug box.

Typically Tempest spark plug resistors will stay between 1000 and 1500 Ohms throughout their life. Tempest specifies that the plug resistor should never be below 500 Ohms or above 5000 Ohms. We offer a lifetime guarantee on our fired-in resistor.

Carbon fouling is indicated by dry, fluffy, sooty deposits. The plug is operating too cold to burn off combustion deposits. This may be fuel related or ignition related. Fuel related causes include rich fuel mixture, faulty carburetor adjustment, excessive idling or improper idle mixture. Ignition causes could be related to a worn spark plug ignition lead, improper magneto timing or running too cold of a spark plug.

Indicated by hard ash-type deposits, lead fouling can be caused by poor fuel vaporization due to cold operating temperatures or high-lead content in the fuel (misdistribution of tetraethyl lead). Lightly fouled plugs can be cleaned, re-gapped, tested and reinstalled using a new copper mounting gasket. Severely fouled plugs should be replaced with new Tempest® spark plugs.

Oil fouling is indicated by oily, wet deposits and frequent misfires. Causes can include damaged pistons, worn or broken piston rings, worn valve guides, sticking valves, faulty ignition supply or an engine during break-in period.

Please visit the Technical Data portion of our website to find our articles on best cleaning practices.

Tempest currently manufactures only 18mm spark plugs.

Please refer to the Tempest application chart. There are several things you will need to know as most engines have several different spark plugs approved.

1. You will need to know your harness B-nut size. This is the nut that screws onto the spark plug. It will be either a 5/8-24” or ¾-20 thread. Be aware that a 5/8-24 utilizes a 3/4” wrench and a ¾-20 utilizes a 7/8” wrench.
2. Long reach v. short reach will be determined by the specific engine.
3. Heat rating is indicated by the numeric value of the spark plug part number. The lower the numeric value the colder the heat rating. Best practice is to use the same heat rated plug you have removed.
4. Massive electrode or fine wire is a personal choice. Massive plugs will generally operate 400-500 hours. Fine wires can last 1500 hours. This choice is usually determined by number of annual hours flown and the size and performance of the specific engine.