How Lean?
 

I have an OS 61FX. I have run 1 gallon of fuel thru the engine at a rich setting, which was 2 turns of the needle valve. (After flying, the fuse and stab were fuel SOAKED). I have read the manual and I guess I'm kinda confused. This is my first engine (I'm still new at this hobby). What is the correct procedure to know that your engine is properly leaned out?


I am using 15% Nitro. I came home and turned my needle valve down to only a half turn from closed, It is still cool enough to touch, but I just dont want to damage it.


Any advice would be great.


Thanks

RE: How Lean?
 

Go to the beginners forum and do a search for tuning engines. That should get you started on the right path.

You can ruin that engine by running it TOO RICH for too long. It's an ABC engine and it needs to get heated up in order to properly break in.

Here's the quick and dirty way to tune it:
Get a tachometer
Run it full throttle and lean it slowly a few clicks at a time untill it stops gaining RPM. When it starts too loose RPM-- you've gone too far. Back it up rich again and then richen it up about 5 or 6 clicks on the rich side.

You will be able to hear it when it gets fully lean at top RPM. As you lean the needle it will gain RPM and then when you get too lean it will slow down again or die. Thats whats called MAX LEAN.

Find your max lean setting and then back it up rich about 5 or 6 clicks. That should do it.

RE: How Lean?
 

http://www.rcuniverse.com/forum/sait...1135642/tm.htm

Enjoy,

Jim

RE: How Lean?
 

You don't really need a tach to set the motor for a rich
enough setting....you can tell by the sound. Start the
motor at about 1/3 throttle, and let it warm up for
about 20 seconds. Open the throttle all the way, and turn
the needle in....till the motor starts to slow down. Quickly
open the needle a few clicks, and it will be running full
speed again....now open the nedle till the motor "audibly"
slows down a bit....you can hear it. Now you are running a
bit rich....right where you want to be. The amount of
richness you need depends on varying factors....but the
bottom line is....you always want it running a bit rich to
avoid over heating the motor.

Ask one of the fellas at the field how to set your motor
on the rich side....if it is too rich, it will be low on power,
and will waste fuel....but generally it will not hurt the motor.

Your motor is an ABN type....(nickel plated bore)....not a
ABC....(chrome plated bore)....which is more durable,
But it is a good motor.

Dave. :)

RE: How Lean?
 

Thank you very much for your information.

RE: How Lean?
 

If you are getting fuel out of the muffler, too rich! If you get no smoke out of the muffler, too lean! I like a little smoke, that tells me the engine has enough fuel to cool, but is still going to be strong enough to pull my plane.