There is always that possibility that I am off by a tooth on the timing belt. It's something I will check after getting the carburetor back on if I still have issues. 

Mine does not have an issue with ignitor in the dizzy, they don't exist on this installation. I am running a dual electronic ignition system that uses magnets installed in the flywheel and two hall effect sensors for the crank position. 

There is a thermostat, using the 170 degrees option. I'll upload a video of the engine monitor and you can see what is happening with temps after shutdown. Challenge have with cooling is that system is designed for cooling in flight with minimal drag. On the ground, I don't get enough airflow through the small radiators. To solve this I added 5-inch high CFM fans. These help a lot, but I still get after-boil. This is why I went with the Evans coolant. 

I am anxious to compare spark plugs. I recently changed them out and when I think back, I realize they did not have my usual plugs in stock and gave me an alternative. What I don't know is if I ended up with a hotter plug as a result. This has been nagging at me since you mentioned it in the earlier post. 

I certainly appreciate all the assistance. 

Interesting, I never even considered hot/cold plugs. I'll definitely look into it. I run the engine between 5,000 and 5,600 RPM always as the prop reduction unit is 2.4-to-1, the prop is only spinning at 2,500 when the engine is at 6,000 RPM

The motor is not rebuilt yet. It has about 600 hours on it and it maintained to a much higher standard than when in a car. Compression tests are performed yearly and compared for the life of the engine. Every other oil change has an oil analysis performed and every oil change the filter is cut open to check for metal and contamination. 

I recently replaced the water pump, thermostat, oil pump (bad seal w/slight leak, replaced the whole thing) timing belt, cam seal, tensioner, etc. 

Temps are about 190-200 on the ground. In flight 180-190. I was having some after-boil issues, so switched to Evans NPG+. Valves are due for an adjustment, its been about 12 months since they were last addressed. 

I'm not sure on the fuel pressure, but the flow was correct. 

I will need to check the timing when I get the carb back on it. I took it off on Friday to rebuild it. Next weekend will have it back on. 

Correct, the EW2 was sourced in Canada and is not CVCC. 

No room for a muffler, but the exhaust was purpose build for the engine configuration. The plugs are new, about two hours on them. But they do show it as running lean already. 

When I removed the carburetor, I noticed that it was about half a thread loose at the connection to the intake. I think this is from compression of the carburetor to intake gasket going bad (was about nothing left of it). 

Are there any Michigan meets?

Some other items. I run 90 REC auto fuel, no ethanol. I need ethanol-free because ethanol attracts moisture and planes are prone to icing in the carburetor. 

There is a dual fuel pump configuration. Both are testing active and flow tests fine. 

The ignition system is dual electronic ignition configured at wasted spark. I'm going up this weekend to verify timing and advance has not changed. 

At the moment, I am leaning toward something with the carburetor but thought I would hit up others that run this engine at over 5,000 RPM continuous or racing it.  I'm new to the Honda platform but overall like it and want to keep it for racing the plane. 

I actually run it continuously at 5200-5800 RPM in flight. The prop acts as a limiter on the ground as it needs to be moving forward to get over 4400-4600 RPM, which is what we consider the correct static RPM. 

Its carburated (stock carb) and has a 4 into 1 stainless exhaust; no muffler. 

Having a challenge with my EW2 and need some advice. 

Please don't obsess over what its installed in. Just listen to the engine at full power (well, actually about 4200-4600 RPM) and provide any thoughts and recommendations you can. 

Thanks a bunch, G