Gas Engine Tuning

Guest Cody Wojcik gives us this ten minute tip on gas engine tuning. Tuning your engine simply means getting the perfect amount of fuel to the engine at all throttle settings. Here are the basic steps:

  • Find the factory needle settings from the manual and open both the L (low speed) and H (high speed) to those settings + 1/4 turn more to assure it’s rich enough.
  • Close the choke, turn on the ignition and flip the engine until it pops. It won’t start and run, but it will pop.
  • Open the choke, make sure the throttle is at idle, and continue flipping. It should start.

If it does not start, try these steps:

  • Remove the spark plug to be sure the engine is not flooded (too much fuel)
  • While the spark plug is out, reconnect the ignition lead and rotate the engine to see if you get spark at the plug
  • Make sure fuel is reaching the carburetor (visually check the fuel line)
  • Use a genuine NGK spark plug (not the stock DLE plug, if that’s your engine type)

Next steps after it’s running:

  • Go to full throttle, make sure it continues to run. It will likely burble and pop from being too rich.
  • Lean the low needle 1/8 turn, then go to full throttle and check response. Keep doing this until when you advance to full throttle the engine bogs and tries to die. Richen the low needle until it responds well.
  • Use a tachometer and check full throttle RPM. Turn the high speed needle in 1/8 turn and take another reading. Repeat until you see no more gain in RPM, then enrichen slightly to bring it 50-100 RPM below peak.

This Ten Minute Tip (TMT) is from RC Today Show Episode 107. If you wish, you can download the MP3 file for just this TMT here.