Extend the Life of Your McFarlane Throttle Control

It is recommended that all engine controls be replaced in conjunction with the maximum time between overhauls for the engine they are paired with. However, you may find that over time, the friction lock mechanism on your McFarlane throttle control does not seem to hold its position as well as it did in the past. We have a solution for that! 

Extend the Life of Your McFarlane Throttle Control

By Matt Sharpton, Sales Associate/A&P Mechanic   

McFarlane Aviation Products has been producing reliable FAA-PMA approved engine controls for over 20 years, with units installed in tens of thousands of airplanes around the world. McFarlane strives to produce safe, high quality products at a reasonable price. The engine throttle control with friction lock is a perfect example of such a product.   It is recommended that all engine controls be replaced in conjunction with the maximum time between overhauls for the engine they are paired with. However, you may find that over time, the friction lock mechanism on your McFarlane throttle control does not seem to hold its position as well as it did in the past. We have a solution for that! McFarlane designed the friction locking portion of the control with the customer in mind. Leather packings installed on the control shaft, inside the friction wheel, can be replaced by your A&P mechanic or repair station at a fraction of the cost of a new control.

Detailed instructions come with each kit, but are summarized by these simple steps:

1. Remove the throttle control knob and jam nut with a rubber gripper and wrench.
2. Remove the knurled friction wheel from the shaft. 3. Remove the old friction packings.
3. Clean the throttle control shaft with lacquer thinner.  (Important: Do not lubricate the shaft or packings).
4. Install the new packings, orienting the first and last washers with the smooth sides facing outwards.
5. Reinstall the previously removed components and cycle the control and friction lock to check for smooth operation.

The knurled friction wheel thread size determines which packing kit you should purchase. The knurled friction wheel with 1/2" thread uses the EC12SK packing kit, while the knurled friction wheel with the 9/16” thread utilizes the EC312SK packing kit. Upon replacing these affordable packings, your throttle control friction lock will function like new again!