Polini Thor 250

The Thor models share a common design.  The info below is unique for the 100.  Please see the Thor all models section for info that is not found here.  The Top 80 section has detailed info on things like the carburetor function and tune up (used by all Miniplane and Polini engines), and troubleshooting issues.

It is a good idea to check Polini's website to get the latest (or additional) information.

Carburetor (not a Walbro) 28mm throat diameter, main jet 118 (according to Polini but it could be something else).  These carburetors are more like the Bing.

Cooling system 1

Cooling system 2


Note Polini updates their parts frequently so these lists may not be 100% accurate.

Dual spark plug parts

Dual spark plug wiring diagram – the dual system employs a magneto and a CDI.  The CDI provides a much more powerful spark and increases the efficiency and power of the engine.  The magneto circuit is the same as the Thor 130.  The resistance of the magneto is about 290 Ohms.

Electric starter parts

Engine parts single spark plug

Engine parts dual spark plug

Frame mounting parts

Fuel system parts

Spark plug – Champion RN2C  gap 0.023"-0.028" (0.58mm - 0.71mm)  Polini does not specify the gap value in their engine manual.  The value here is from Champion's technical site.  I suggest that pilots use the lesser gap value because of this engine's high compression.

Specifications & torque values – see "User manual" below

Thermostat parts

User manual (single and dual spark plug)

Wiring diagram

Turkey Vulture