sunset flight near TN river 2024-11-17

Wind less than 5 mph temps high 60s.
The weeds are growing and will probably get too tall to make it launch in this field probably in a month unless they decide to plant something.
Was going to do a second flight but the engine wouldn't hold max RPM like it was starving for fuel, I thought it was the fuel pump Ive been testing but doesn't appear to be the case. I took a quick look when I got home and noticed the mounting bracket for the breather and cables was cracked again but was at least holding together. Im going to have redesign something using phenolic and drop the filter altogether and just put a wire mesh screen to keep debris out on launch. The manual decomp valve was dribbling a bit and probably needs cleaning. Not sure why between shutdown and a few minutes later it wouldn't hold rpm.

[@SagaSeaCraft]

You may want to add a manometer (teed and vertical tubing with a valve) after your external fuel pump to verify that the fuel pressure is what you expect.
I installed a Mikuni diaphragm pulse pump (pulse from intake manifold pressure fluctuations) to add pressure to my carb, with a return line to the fuel tank via a 1psi check valve. I put a manometer just after carb, teed to the fuel return line to verify that it's generating ~1psi fuel pressure to the carb throughout the full rpm range. I use a manual valve to isolate the manometer from the fuel system when flying or when not in need of verifying fuel pressures.
Also, check that the fuel tank's ventilation system is venting absolutely freely. If it's stock, it's likely that it has a spring check valve in the vent system and that valve doesn't open unless there is some vacuum in the tank, which is NOT good and may create fuel starvation issues. I made a completely open tank ventilation system that can be closed by a manual valve when not flying.
As I indicated in another vid of yours, I've been running 24:1 100LL/Motul 800 road-bike 2t oil. I popped the cylinder head off this weekend and was amazed at the condition of the piston deck and head. Even after idling the engine for much of the time, with a 30-second WOT to clean out the carbon on the ground, the piston deck was very clean, the head had just a slight smear of soft carbon in the dome that easily wiped off. The squish band was completely clean. Plug was tan-colored with a black ring at the insulator base. The caveat is that I had retarded the ignition to 21 degrees BTDC because I had made the squish clearances as close as possible (0.45mm) and wanted to keep internal CHT temps to the minimum for the time being until I know that there won't be any interference problems due to heat-related lengthening of the con-rod. So far so good. I am planning on advancing the timing to around 24 degrees BTDC. At stock timing (26.2 degrees), typically I see 9700-9800 rpm static with a 54 x 22.5" pitch prop, but with the timing retarded, it's only getting to ~9400 rpm.