What is the Kickback Protection System (KPS)?

The Kickback Protection System (KPS) protects the starter from damage if the engine kicks back during start. The system uses a sacrificial shear pin designed to fail before internal starter components are damaged. The shear pin can be replaced in the field if needed.

How do I know if the shear pin needs to be replaced?

If the starter motor spins and the pinion engages the flywheel but the propeller does not turn, the shear pin may have failed and should be replaced.

Does the starter drive need lubrication?

If the starter uses a mechanical Bendix drive, it may occasionally need cleaning and lubrication with silicone spray only. Oil or grease should not be used because they attract dirt and can cause the drive to stick.

How do I determine whether my engine has a 122-tooth or 149-tooth ring gear?

Lycoming ring gears can typically be identified by their shape:122-tooth gear: V-shaped tooth profile149-tooth gear: U-shaped tooth profileAlways verify the ring gear configuration before ordering a starter.

Can XP starters replace older Bendix-drive starters?

Yes. Sky-Tec XP starters are designed as modern replacements for legacy Bendix-drive starters, offering lighter weight, improved efficiency, and kickback protection.

Why does my Lycoming engine kick back during start?

Engine kickback is usually caused by improper magneto timing, weak battery voltage, or ignition firing too early during start. Kickback events can damage starters, which is why many modern starters include kickback protection systems. If kickback occurs frequently, inspect the magnetos, ignition timing, and battery condition.

What would cause the drive gear to break on my starter?

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.

What would cause drive gear wear and/or a damaged ring gear?

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.

Does the starter drive need to be lubricated periodically?

Sticking mechanical starter drives, e.g., Bendix drives, should be cleaned with mineral spirits and only lubricated with silicone spray. Oil or common greases should not be used as they will attract and retain dust and grit causing the starter drive to stick or wear rapidly. Solenoid-actuated starters do not require any type of cleaning or lubrication. If the starter is not going to be used for some period of time the shaft can be oiled to prevent corrosion.

Why does my starter engage intermittently?

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.

After the start button is released, why does the starter appear to briefly remain engaged?

This is normal for a permanent-magnet starter. Although power is removed by releasing the key/start button, a permanent-magnet motor will actually provide power to itself as it winds down and will keep the starter drive engaged for about a half-second until it loses sufficient RPM to fully disengage.

Why does the starter drive gear remain engaged for an extended length of time after the start button/key was released?

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.

Why is my new lightweight starter noisy?

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.

How can I tell whether I have 122 teeth or 149 teeth on my Lycoming ring gear?

122 tooth gear rings have a "v" shape, whereas 149 tooth gear rings have a "u" shape. Be aware that just because your aircraft (or engine) is supposed to have a certain ring gear doesn't necessarily mean that it does. You should always confirm and order the correct starter to match.

Why doesn't the NL Starter work well with a Superior engine?

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.

When replacing a B&C or Kelly starter with a Sky-Tec, why doesn't the alternator strap fit properly between the starter and alternator? What bolt should be used to secure an alternator strap to the starter's alternator boss?

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

How do I replace the shear pin on an NL Starter?

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.

What is the Kickback Protection System (KPS)?

The Kickback Protection System (KPS) protects the starter from damage if the engine kicks back during start. The system uses a sacrificial shear pin designed to fail before internal starter components are damaged. The shear pin can be replaced in the field if needed.

How do I know if the shear pin needs to be replaced?

If the starter motor spins and the pinion engages the flywheel but the propeller does not turn, the shear pin may have failed and should be replaced.

Does the starter drive need lubrication?

If the starter uses a mechanical Bendix drive, it may occasionally need cleaning and lubrication with silicone spray only. Oil or grease should not be used because they attract dirt and can cause the drive to stick.

How do I determine whether my engine has a 122-tooth or 149-tooth ring gear?

Lycoming ring gears can typically be identified by their shape:122-tooth gear: V-shaped tooth profile149-tooth gear: U-shaped tooth profileAlways verify the ring gear configuration before ordering a starter.

Can XP starters replace older Bendix-drive starters?

Yes. Sky-Tec XP starters are designed as modern replacements for legacy Bendix-drive starters, offering lighter weight, improved efficiency, and kickback protection.

Why does my Lycoming engine kick back during start?

Engine kickback is usually caused by improper magneto timing, weak battery voltage, or ignition firing too early during start. Kickback events can damage starters, which is why many modern starters include kickback protection systems. If kickback occurs frequently, inspect the magnetos, ignition timing, and battery condition.

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Home / Shop Parts ... / 122NLXP

P/N: 122NLXP

Name: STARTER, EXPERIMENTAL, 12V, 122 Tooth
Brand: Hartzell Engine Technologies
SKU: 122NLXP
Price: 1042.94 USD
Availability: InStock

STARTER, EXPERIMENTAL, 12V, 122 Tooth

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Condition	New
Manufacturer	Hartzell Engine Technologies
Dimensions	L: 8.5 x W: 6 x H: 15.25 in
Weight	11.5 lbs
Unit of Measure	Each
Retail Price	$1,303.69
Your Price	$1,042.94
Stock Status	In Stock

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Image	Part #	Description	U/M	Retail Price	Your Price	Stock
	149NLXP	STARTER, EXPERIMENTAL, 12V, 149 Tooth		$1,303.69	$1,042.94

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Sky-Tec Starters

122 and 149 XP Experimental Series Lycoming Starters

The Sky-Tec XP experimental starters, manufactured by Hartzell Engine Technologies, is designed specifically for experimental and homebuilt aircraft. These starters provide a lightweight, factory-new alternative with dependable starting power and modern protection features for Lycoming-powered experimental aircraft.

Lightweight
New production alternative to rebuilt or overhauled options
Built-in Kickback Protection System (KPS)
Field-replaceable shear pin helps protect starter components
Direct replacement for legacy Bendix-drive starters
Designed for 12V electrical systems
6-month warranty

Kickback Protection System (KPS)

Protects starter motor and drive system during engine kickback
Uses a sacrificial shear pin to prevent internal damage
Shear pin can be replaced in the field

Series Options:

HTXP: HT Series starters have a high torque motor, ideal for higher compression engines or difficult starting conditions
NLXP: NL Series are the most popular Skytec series for Lycoming engines with an excellent balance of weight, performance, and reliability
LSXP and PMXP: PM/LS Series are lightweight and compact, based on the original Sky-Tec Flyweight design

For the Sky-Tec fit guide, click here.
For Continental starters, click here.

To compare all the Sky-Tec starter series options, click here.

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