Rotax issue Service Bulletins alerting owners of known issues or defects that need addressing. The first was to replace the carbruettor floats that have been found to be soaking up fuel and sinking. This could cause rough running or even engine failure. I changed these before the first flight to ensure my test pilot wasn’t at risk.

The latest one applies to my engine and relates to a circlip that holds the jet needle in place. The reason stated was ‘Due to deviations in the manufacturing process a partial fracture of the circlip may occur. This fracture might lead to a crack/ total fracture of the circlip which in consequence may lead to a malfunction of the carburettor. Possible effects might be rough engine running or an unusual engine operating behaviour.’ The replacement needed to be done within 25 hours of the notice issue date but in any event no later than 31st July 2020. Replacement circlips and the ‘O’ rings were supplied under warranty from CFS

As the engine is just coming up to 25 hours and with Maypole’s runway waterlogged it was an ideal time to carry out the change.

Overall the process was very straightforward. The first carb took 45 minutes to do but the second was much quicker at 30 minutes. The engine logbook has been updated and the engine will be test run to check for correct operation before the next flight.

Let’s hope there’s not too many more of these mandatory service bulletins affecting my engine!