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How to Check an RC Engine Without Fuel

RC airplane engines are either simple two-cycle engines or more complex four-cycle engine. An engine needs to have good compression to produce enough power to fly the plane. The most common way to test an engine is to put it on a test stand and run a tank of fuel through it. When that's not an option, you can still evaluate the engine by performing other tests.

Things You'll Need

Glow plug wrench
Phillips-head screwdriver
Propeller

Instructions

- 1
  Remove the glow plug from the engine's head. Use a glow plug wrench to avoid damaging the plug. Be careful not to lose the copper ring that sits between the plug and the head.
- 2
  Attach a prop to the engine and turn it counter-clockwise. The engine should turn easily without feeling sticky or gummed up. Any resistence is an indication that either the engine was stored with fuel in it or that the crankshaft or piston is damaged.
- 3
  Reinstall the glow plug and test the compression by turning the prop again. This time, it should be more difficult to turn the prop when the piston extends into the cylinder. Listen for escaping air as this is a sign that the head is loose.
- 4
  Remove the head by removing the screws that hold it to the cylinder. Once it is off, look at the chamber where the glow plug sits. If it is black with carbon, then clean it well with a rag. Carbon deposits are indicators that either the glow plug is old or the engine has been run with low nitro content fuel. Reattach the head by installing the screws, using a star pattern when tightening the screws to prevent warping the head.
- 5
  Remove the muffler and check the gasket that sits between the muffler and the engine. Look for any carbon deposits and clean and remove any you find. Blow some air into the muffler and make sure it passes through the muffler. A clogged muffler will cause the engine to perform badly.

Aviation