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How do I know which screw kit to use?

The screw kit depends on if the holes in the floor of your airplane have been carefully removed and are close to new size or if they have been enlarged by unskilled rivet removal or the rails have been changed before. It will make a difference if the previous rails installed were Cessna rails with predrilled holes in the rail. (They do not normally line up well and the floor has been mis-drilled some to force them to align). If the holes are good, use the SR6-SCREW-KT kit. If the holes are enlarged some, use the SR8-SCREW-KT kit.

What if there is some resistance to the MC0511242-1 Seat Stop entering the hole in my new McFarlane manufactured Seat Rail?

Installation of the McFarlane Seat Stop P/N MC0511242-1 may require the removal of extra material from the seat rail where the seat rail hole breaks through the vertical web. Material removal may be accomplished with a small file or other deburring tool. Do not remove material from the seat stop when attempting to install. Refer to Cessna/Textron service information for correct seat stop location.

What is the standard hole depth for drilling additional holes in seat rails?

Determine which extrusion is used: STE101 and STE102 - Standard hole depth drilled on the roller flange is .330” and standard diameter is .277”. STE103 and STE104 - Standard hole depth drilled on the roller flange is .280” and standard diameter is .277”.

What does temperature compensated mean?

When hydraulic oil changes temperature, the volume of the oil also changes. This volume change from a temperature reduction will create a vacuum in the oil chamber of the original Cessna uncompensated shimmy dampener. This vacuum will cause the oil to vaporize giving the oil a foamy expanded mixture that is compressible. The shimmy  dampener action is then drastically degraded. An increase in temperature will increase the oil volume causing a drastic pressurization of the dampener oil chamber. This pressure will force small quantities of oil past the dampener shaft seals. The decrease in oil will then aggravate any temperature reduction with increased chamber vacuum and related oil vaporization. This process explains why continuous servicing of the original shimmy dampener is required.

The temperature compensation system works by having a small chamber of oil that is spring pressurized through a very small passage into the main dampening restrictive orifice of the shimmy dampener. The spring loaded oil chamber can adjust for oil volume changes as temperature changes. A similar system is built into your car shock absorbers. The temperature compensated hydraulic system requires very little service over extended periods of time and assures stable shimmy dampening action.

Why is a hydraulic shimmy dampener better than a rubber dampener?

A rubber based dampener is continuously fatiguing the rubber components as it changes direction of motion. The rubber system depends on stable friction of the rubber riding in a metal tube. This is very difficult to achieve over extended usage. There are inherent differences in static friction of rubber and dynamic friction of rubber that affect dampening performance. Long term use changes the performance of the dampener caused by all of these un-repairable factors. The hydraulic system works in a film oil with stable performance for long periods of time and it is totally repairable.

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.

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.

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. 

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 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.

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.

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. 

Why does my starter engage but the engine won't turn over?

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

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.

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 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.

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.

Does this Tempest Spark Plug Thread Lubricant contain copper?

No, this does not contain copper.

Does this prodcut part #12-00709 have a shelf life expiry?

No, this prodcut does not have a known shelf life.

How can I check my spark plug resistor?

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.