Chris,

While the Evo was tested by prominent R/C magazines and was found to be a high performance, well made engine, I believe even new modelers should be tought to run and to adjust engine by being "thrown into the water" and being forced to start swimming... Not with concessions and "E Z Adjust" engines.

In your post, it is not clear if you tried to adjust the idle mixture needle.
Since you are new to engines, you will first have to learn to determine, by its response behavior, if your engine's idle is adjusted too lean, or too rich.


I copied this from a previous post, that I replied with to another asker...
I adjusted the reply for your Evo...

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Start the engine and advance the throttle slowly to full power. With the nose pointing straight up, adjust the main needle 100-200 RPM richer than maximum (lean it to max and then open it a few clicks).

Lower the plane to level attitude and close the throttle to idle; about 1mm from fully closed. Now listen; if the engine is gradually slowing down, it is too rich. If, on the other hand, it is speeding up gradually, it is set too lean.

Because adjusting the idle needle requires close proximity to the spinning prop, some will say you should shut the engine down for adjusting this needle. If you are sure that you are competent enough, you can do it with the engine running at 1/4-1/3 throttle. Adjust this needle at flying attitude (level for most planes)

Let us assume you determined the idle is too rich. Close the idle needle very little, run the engine at full throttle for a few seconds, to clear it of excess fuel and close the throttle back to idle. Listen again as described in the third paragraph and repeat the adjustment in ever smaller incremental changes, until the idle speed is steady.

If the idle was too lean, do the same, but open the idle needle a little at a time, instead of closing it.


Now the transition test. Your idle is steady. Run the engine at full throttle for a few seconds and close the throttle to idling position. Allow it to idle for 30 seconds (which may seem longer than you think...) and open the throttle to full QUICKLY.

If the engine ran to full immediately and rapidly, you are done. If it hesitated; sort of choked and then sped up to full (or died), it is a bit too lean. Open the idle needle very little and repeat this test.

If, on the other hand, the engine sputters (and sometimes spits fuel out of the carburettor), before speeding up, or dieing, the idle circuit is set a little too rich. Close the idle needle very little and repeat this test.


Do this until you are happy with the idle quality and the response. If you are flying a 3-D model, you will need the idle set richer than a regular plane, because the engine must overcome gravity, to get the right amount of fuel for a good transition and part throttle operation (the idle needle controls the fuel mixture from 0-80% throttle).