scottmillhouse
Well Known Member
First stock RV-7A with new Lycoming IO-360, Hartzell CS prop, 60 hours time since new. For first few hours I had high CHT across the board. Eventually traced to one of the new mags timing drifting over first few hours. Stopped at about 10 hours and has not drifted at least at last check about 10 hours ago.
Yesterday a typical flight only difference at landing with power pulled the engine appeared to be miss firing. Slight noise but could feel the exhaust misfiring pulses under my feet. Upon taxi from Savvy analysis of Dynon data showed 1000-1400rpm with #4 climbed over 2 minutes from 325-480. No evidence of any blockage. Initially assumed a malfunctioning CHT. Upon startup and taxi temperature was about 400 for #4, run up normal, back taxi about 20 knots did not cool but stayed about 400. Did another runup and #4 immediately climbed in 15 seconds to over 500 before I shut down. Audible misfire noise at shutdown and high temperature smell. For all events EGT stayed in line with other cylinders with no other parameters out of line. Shutdown runway for a few minutes to cool. Challenging IO hot start but then taxi to FBO temperatures stayed in safe zone. Let cool a half hour with another challenging hot start but they otherwise normal to circle and climb high just in case before heading home. Being late I just hangered it.
I plan to pull cowl and check timing, compression, remove and clean all fuel filters and flush fuel injection. Any ideas from the brain bank on what happened and what to look for?
Yesterday a typical flight only difference at landing with power pulled the engine appeared to be miss firing. Slight noise but could feel the exhaust misfiring pulses under my feet. Upon taxi from Savvy analysis of Dynon data showed 1000-1400rpm with #4 climbed over 2 minutes from 325-480. No evidence of any blockage. Initially assumed a malfunctioning CHT. Upon startup and taxi temperature was about 400 for #4, run up normal, back taxi about 20 knots did not cool but stayed about 400. Did another runup and #4 immediately climbed in 15 seconds to over 500 before I shut down. Audible misfire noise at shutdown and high temperature smell. For all events EGT stayed in line with other cylinders with no other parameters out of line. Shutdown runway for a few minutes to cool. Challenging IO hot start but then taxi to FBO temperatures stayed in safe zone. Let cool a half hour with another challenging hot start but they otherwise normal to circle and climb high just in case before heading home. Being late I just hangered it.
I plan to pull cowl and check timing, compression, remove and clean all fuel filters and flush fuel injection. Any ideas from the brain bank on what happened and what to look for?