Rans COYOTE II S-6ES, Technical Manual

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020240cg msw 09/01/05
024-15
KEEPING YOUR 2-CYCLE ROTAX ENGINE CARBON FREE
The Rotax manual as well as the following information outlines some excellent procedures to assure reliable
operations. However, in the real world the method suggested for carbon removal is only a half-way measure.
True removing the cylinder heads and scraping the dome and piston top will prevent carbon from fouling the
plugs. But we go one step further by removing the cylinders and then the pistons. Why? To clean the ring
grooves. Yes, for the first 200 hours it is
VERY important to clean the rings and pistons every 50 hours.
Sounds tough but it is not bad if you are careful (and easier than fixing airframes). Use an aluminum scraper
and be careful when removing the rings not to bend them it get them mixed up. Do one piston and reassemble
it to the rod.
THEN do the other. You will be surprised at the carbon build! Now if you do not see stuck rings
or carbon DO NOT clean it! You are a lucky one, but do inspect it regardless. After 200 hours you may opt to
go to 65 hours instead of 50. You will know by the condition of the engine from previous inspections. A ring
stuck by carbon build can cause seizures because of blow by and localized hot spots. The piston skirt heats
and swells until it sticks. Carbon free rings will assure this potential failure is eliminated.