Thor 303 Electronic Ignition Recall Campaign

July 17, 2023
whole image of motor black in color
Thor 130


WARNING: Polini Motori has been notified by some partners of technical problems on a few Thor 303 in USA. The main one is due to self-ignition phenomenon that may lead to and have already led to hole the piston. The main causes of this situation is the use of low octanes fuel or fuel with ethanol or propeller with too much pitch. Polini Motori underlies the importance of what has been already written in the “User manual” supplied together with all the engines, at chapter 2, for American users of Thor engines: FUEL: WARNING! For American customers only. The European range of octane is different from the American one: e.g. EU 95 OCTANE = US 91 OCTANE / EU 98 OCTANE = US 93 OCTANE For THOR engines you have to use a high-octane fuel (not less than US 91), max 5% ethanol. !WARNING! it is important to use 100 LL AVGAS in case of unavailability of the fuel recommended above. The information collected from the users that has experienced these problems underline all the use of the same fuel called “US 90”. Instead Users that have used fuel with the specifications as per our manual, as predictable, did not have any failure. To solve this situation Polini Motori has developed for Thor 303 a new head with specific geometry and compression to limits the phenomenon of self-ignition even with the use of US90 fuel. It’s VERY IMPORTANT anyway to use AV-GAS 100LL fuel. In fact this type of fuel has 100 octanes and it ethanol-free thus granting high benefits to the engine, to all its mechanical parts, rubber manifold and makes the engine life longer. 


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