bjohnson1234
Well Known Member
I have a Mattituck XP-360 that has a stuttering issue. It's either not noticeable at cruise RPM or it doesn't happen, but I have definitely noticed it in flight and on the ground. Every 3 or 4 seconds it very briefly loses some power, maybe a drop of 50 RPM or so and then spins back up. It's both audible and visible in the prop. I have sent my engine data to savvyanalysis and everything came back looking good, so I'm pretty sure it's not ignition, intake leak or sticking valve. It also seems to happen more frequently when the engine is hot (maybe always?). I checked the timing recently and savvyanalysis confirmed that it's correct. I have a fixed pitch prop, so it's not a governor issue. All my fuel lines have firesleeve and I cleaned out the fuel filter in the fuel injection servo. I also checked to make sure there are no broken springs on the valves. Everyone I've spoken to is stumped. Has anyone else seen anything like this? Any ideas what it might be?