Fired up the engine for the first time today. Below there’s a video of the event recorded by my son Luka.


Adding fuel 1/2 gallons at a time, I marked the fuel level on the tank up to 3 gallons. Sitting in the plane, I can only see up to 2 gallons but it could be useful in a pinch.

The AeroVee manual says to prime the oil first. This involved removing 4 spark plugs, 1 from each cylinder, and making sure the oil pressure sensor reads an increase in pressure when running the starter. Mine read 57 PSI before I touched the starter, and it never budged. That’s not right! Dynon support says it’s likely a faulty pressure sensor (Kavlico 150 PSI). Apparently they’ve had a few similar reports with these sensors so they’re sending me a new one. I had a spare “legacy” mechanical sensor so I connected that one and it worked. No show stopper here.

I pulled the plane out to the basketball court again, chained it to the post, put the parking breaks on, and put chocks under the tires. Who know what could happen and you can’t be too safe.

Test Location

First Engine Test

Luka came out to assist. His job was to check for leaking fluids and film the event.

On the first try, the engine popped a few times. Perhaps I was too gentle on the throttle, or perhaps the engine needed a few moments to stretch a bit before coming to life for the first time. But it didn’t take long to get it running steady… and boy did it get windy!

OneX First Engine Start from Micah Martin on Vimeo.

Amazing! I’d never built an engine before. It’s fascinating that a newb like me can put all those engine pieces together and get a working engine that starts on the first test.


You’ll see in the video that once the engine is running, I’m checking all the sensors and performance. Most everything worked great but there are a few problems I need to investigate:

  • The RPM indicator showed 0 when I turned the alternator on.
  • The battery didn’t charge and eventually died.
  • Although the magnetos worked great, the ignitions were intermittent. When I turned the mags off, the engine would sputter and threaten to quit.
  • The RPMs were a bit unsteady, tending to rise and fall without any change in throttle, except at idle.
  • A small amount of oil leaked out from the oil cooler mount, drain bolt, and oil pump.

With the plane back in the garage, I tightened some bolt to seal the oil leaks. And with some quick research, I discovered that I may have connected the RPM sensor lead to the wrong terminal on the voltage regulator. This may be the cause for most the other problems. I swapped the leads and we’ll see how that helps tomorrow. When I reposition the AeroInjector, that may help with the sporadic RPMs. I’ll report in a later blog.