Polini Thor 250

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

Dimensions

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

Dual spark plug parts

Dual spark plug wiring diagram

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.

Thermostat parts

User manual (single and dual spark plug)

Wiring diagram

Turkey Vulture

USHPA
USPPA