Please fill out the form below for Engine and get a quote for part number O540E4B5 RT9961 by Lycoming Mfg Co, please include required quantity along with expected turn around time. Our knowledgeable account manager will reply you shortly. Also check for the related parts for part number O540E4B5 RT9961. ASAP Aerospace distributes nose to tail NSN components, sub-assemblies, and assemblies for the aerospace and aviation industry.