My RV-8A has 11.8 hours flight time. It's powered by an Aerosport Power IO-360B2B engine. The engine had an additional 3.5 hours of test time at Aerosport Power before it shipped seven years ago. Until today the engine ran just fine. I have a dual Lightspeed ignition.
Today, during run-up prior to take-off, the number 4 cylinder suddenly spiked very hot - both in CHT and EGT. I immediately shut it down. After letting the engine cool down for about 30 minutes I re-started it and taxied back to the hanger. At low idle for a couple of minutes the #4 temps seemed normal. Anything above idle causes #4 to get quickly very hot again.
I changed the oil at 10 hours and flew the plane last week after the oil change for 1.4 hours without any issues. I don't think my problem has anything to do with cowling or baffling. Normal temps during the prior engine break-in flights are CHT 375 and EGT 1270 degrees with less than a 30 degree spread between the four CHTs.
The plugs on #4 look normal compared to the other plugs (just a slight amount of carbon fouling) and the engine didn't seem to run rough - it's just a hot #4. So, I'm thinking the problem with #4 is a clogged or restricted injector. Or perhaps a sticky valve.
Anything else I should be looking at??
Today, during run-up prior to take-off, the number 4 cylinder suddenly spiked very hot - both in CHT and EGT. I immediately shut it down. After letting the engine cool down for about 30 minutes I re-started it and taxied back to the hanger. At low idle for a couple of minutes the #4 temps seemed normal. Anything above idle causes #4 to get quickly very hot again.
I changed the oil at 10 hours and flew the plane last week after the oil change for 1.4 hours without any issues. I don't think my problem has anything to do with cowling or baffling. Normal temps during the prior engine break-in flights are CHT 375 and EGT 1270 degrees with less than a 30 degree spread between the four CHTs.
The plugs on #4 look normal compared to the other plugs (just a slight amount of carbon fouling) and the engine didn't seem to run rough - it's just a hot #4. So, I'm thinking the problem with #4 is a clogged or restricted injector. Or perhaps a sticky valve.
Anything else I should be looking at??