QUESTION: I have a Rotax 912 and am concerned about lead buildup in the engine using 100LL. Will TCP reduce the problem?
ANSWER: I”"ll step out of my box on this one because I think my answer will apply across the board regarding the use of TCP. Many operators over the years have used this product to relieve lead fouling of spark plug symptoms and, from the feedback I’ve heard, sometimes it works and sometimes it doesn’t.
There may be other contributing factors, but here’s what I’d suggest: First and foremost, the use of TCP must be approved by not only the engine manufacturer, but also the airframe manufacturer. For example, Lycoming has a Service Letter L190 regarding the use of TCP. It basically tells you that TCP has no harmful ingredients that would cause problems or affect the engine operation or components. Secondly, it clearly states that you should also obtain similar approval from the airframe manufacturer so that you are confident its use will have no ill effect on fuel tanks/cells, lines, etc.
There is another approach used on the Lycoming engines that may be an option for you, too, and that is going to a hotter spark plug, but I’d check with Rotax to see if this is an option for you. Remember, I know nothing about the Rotax engine you mentioned, so I”"m only responding to the use of TCP from a common-sense standpoint.
Paul McBride, recognized worldwide as an expert on engines, retired after almost 40 years with Lycoming. Send your questions to: AskPaul@GeneralAviationNews.com.