Rotax four stroke aircraft engines have proven themselves as reliable pieces of machinery. They can be bought as experimental (UL) or certified (A and F) engine and there are four main models (injected too) to date. The original engine is the 80 hp 912, from which the 100 hp 912S was developed and Rotax also has a 115 hp turbocharged 914 engine. In 2015 Rotax announced the 135 hp fuel injected turbocharged 915iS.
Due to deviations in the manufacturing process of the valve push-rod assy., partial wear on the rocker arm ball socket may occur. This wear might lead to a rocker arm cracking / fracture which in consequence may lead to a malfunction of the valve train.
This check / repair involves removing the cylinder covers and performing a check on the pushrod heads and the valve rockers.
SB-912-070-i-008-914-052, Pushrod manufacturing deviation.
Excerpt from the document:
Inspection and/or replacement of the valve push-rod assy., rocker arm left and rocker arm right for ROTAX® Engine Type 912 i, 912 and 914 (Series).
Carry out this inspection on the engines listed in section 1.1., according to the instructions in section 3 at the next ROTAX® scheduled maintenance event or within the next 25 hours of operation, but at the latest after 200 days (from the date of the initial issue of this Service Bulletin).
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