Leaking fuel or too rich?

[davidbjr81]

Hi I have a 600 nitro with an OS 50sx-h I noticed some nitro spilling out the carbrator where the throttle adjustment is out of where the shaft connects. I tightened a screw and it stopped. I get seven minutes flight out of a full turn of the needle. Is that normal some people said I should get ten.

[meowguy]

Length of flight time is a very unreliable way to set the mixture on two stroke model engines. The sound, the amount of smoke produced, and the temperature of then engine, are the three indicators I use. Start with the needle settings recommended by the engine manufacturer.

The sound should be a little on the throaty side, not screaming. The Temp should be between 115 and 150 degrees, and there should be a nice plume of white smoke coming out the muffler tail pipe.

See if you can find a mentor who can help you get it adjusted properly and teach what to look for.

[Number]

Sound is the best way to tune. Temp works but only to a point. In the summer/spring, feeling the backplate is a good way - you should be able to hold your finger on the backplate pretty much indefinitely - but in the winter this doesn't work so well, as the engine will run lean but still come down cold, hence why sound is better. If it's rattling, almost a pinging sound, it's way too lean. There should also be plenty of smoke. But if you let it idle for a couple minutes and there's a big puddle of nitro on the ground under the exit of the muffler, it might be a little rich...