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.

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Home / Shop Parts ... / F12ST2

P/N: F12ST2

Name: STARTER, 12V
Brand: Hartzell Engine Technologies
SKU: F12ST2
Price: 1830.51 USD
Availability: BackOrder

STARTER, 12V

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Approval	FAA PMA
Condition	New
Manufacturer	Hartzell Engine Technologies
Dimensions	L: 16 x W: 6 x H: 8 in
Weight	10 lbs
Unit of Measure	Each
Retail Price	$2,288.14
Your Price	$1,830.51
Stock Status	Expected ship date is 10-19-2026.

Eligible Aircraft

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FAQs

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Reference only: Please verify the product is eligible for your aircraft before adding to your cart.

OEM Part Number	McFarlane Part Number	Comment
11009651	F12ST2
20719	F12ST2
F12ST1	F12ST2
MCL-6225	F12ST2
MCL-6502CWDE	F12ST2
MZ4203	F12ST2

Frequently Asked Questions

Eligible Aircraft

Make	Model	End S/N	Eligibility Chart
Franklin	4A-235-B3	ZZZZZZZZZZZZZZZ	7797
Franklin	4A-235-B31	ZZZZZZZZZZZZZZZ	7797
Franklin	6A-350-C1	ZZZZZZZZZZZZZZZ	7797
Franklin	6A-350-C1	ZZZZZZZZZZZZZZZ	7797
Franklin	6A-350-C1R	ZZZZZZZZZZZZZZZ	7797
Franklin	6A-350-C1R	ZZZZZZZZZZZZZZZ	7797
Franklin	6A4-150-B3	ZZZZZZZZZZZZZZZ	7797
Franklin	6A4-150-B31	ZZZZZZZZZZZZZZZ	7797
Franklin	6A4-165-B3	ZZZZZZZZZZZZZZZ	7797
Franklin	6A-335-B1A	ZZZZZZZZZZZZZZZ	7797
Franklin	6A-335-B1A	ZZZZZZZZZZZZZZZ	7797
Franklin	6V-335-A	ZZZZZZZZZZZZZZZ	7797
Franklin	6V-335-B	ZZZZZZZZZZZZZZZ	7797
Franklin	6V-350-A	ZZZZZZZZZZZZZZZ	7797
Franklin	6V-350-A	ZZZZZZZZZZZZZZZ	7797
Franklin	6V-350-B	ZZZZZZZZZZZZZZZ	7797
Franklin	6V-350-B	ZZZZZZZZZZZZZZZ	7797

Eligibility Chart 7797 Notes

Related Categories

Product Details

Sky-Tec Starters | Franklin Starters

ST2 Series

For use with all 4-cylinder Continentals
Kickback Protection System- self-resetting
Click here for the Sky-Tec Fit Guide.

Part Number	Condition	Series	Voltage	Weight (lbs)	Kickback Protection	Notes
F12ST2	New	ST2 Series	12			For Franklin Engines

For Performance Issue test procedures, click here.

Note: A *refundable core charge is included in the price of all Sky-Tec Starters
*When a qualified core is returned within 30 days of the original invoice date.

Warranty Policy
All starters except E-Drive, X-Drive, PM1207, and PM2401 can be accepted for warranty consideration up to 24 months/1000 hours. E-Drive, X-Drive, PM2407, PL13459, and PL13484 can be accepted for warranty consideration up to 36 months/1000 hours.

WARNING: Cancer and/or Reproductive Harm - www.P65warnings.ca.gov