Choke control for the Polini
by Had Robinson
Note: as of June 2017, Polini apparently has seen the light and is supplying choke controls on their engines.
The Thor models come from the factory without some way to apply the choke while sitting in the harness. This is both an inconvenience and a safety issue. What is a pilot to do if he shuts off his engine at high altitude to thermal or ridge soar and then desires to restart it much later? It is impossible to re-prime the engine in the air so the choke must be used.
Also, what if there is a failure of the kill switch? What if he has a runaway engine at the same time?
Fortunately, it is easy to add a choke control, even a temporary one.
Permanent Choke Control
The Top 80 choke control, if modified slightly, works well with the Polini engines. It can be ordered from Miniplane-USA. Because the choke lever on the Polini works in a vertical orientation, the end of the control for the Top 80 must be carefully straightened using a heat gun.
Secure the upper end of the choke control to the engine frame with a nylon zip tie. A small hole must be drilled in the frame for the zip tie.
The lower end of the choke control must be mounted to the frame with a strap and screw (they are supplied with the control). Carefully drill a hole in the frame for the screw.
Temporary Choke Control
For a temporary fix, pilots can use a piece of steel bailing wire long enough to go from the choke lever down to base of the frame.
Connect one end to the choke lever on the carburetor and run the other end down the frame, make a loop in the wire at the end. Pull down on the loop to choke (flood) the engine which will stop it quickly. Because the wire is flexible, it might be difficult to return the choke lever to the off position.