[NSRCA-discussion] Break-in procedure for OS140

[Mike Hester]

I am going to write a full "care and feeding" article for the OS 140 for the July K-Factor, but here's a good start.

First, set your low end screw parallel to the cylinder. 12 o'clock, straight up and down. leave it there for the duration of the break in.

Use an APC 17x10N prop. use an OS F plug.

back the high end needle out 2 full turns. if you plane has a chin cowl, remove it. This engine gets hot for the first run or 2 on the ground.

Crank the engine with a very high idle. Remove the igniter and then advance the throttle to full power after about a minute. It should be spitting rich.

Turn the high end needle until it gets some good RPM but still very rich. You should be putting out some serious smoke. let it run this way for about 5 minutes, no more.

Shut the engine off, and let it cool for about 1/2 hour. the more, the better.

Fill the tank, crank it again, run it to full. This time go in on the needle about 2 clicks and use that for the reference. About every 30-45 seconds, lean it until it goes to max RPM, and not ANY further. Let it run this way for about 5 seconds, and richen it back up. Cycle it this way for about 7 minutes. Shut down the engine, let it cool again.

Crank the 3rd time, and run it at the same setting for about 2 minutes. Now lean it a couple of more clicks, and it should be still putting out some serious smoke, but a little closer to full. Step back, and let it run wide open for a minute, then begin throttling it back and forth every minute or so. Run the tank out like this.

put it together and go fly it. Don't touch the needle. When you get to the bottom of the 1st gallon, go in with the needle ONE click every flight until you get max power. When your low end changes, set the low end (always more lean, but not a whole lot. When you play with that bottom end, a little goes a long way. Like 1/8 of a turn or so.

There are a lot of diffferent ways to do it; some people just set it rich and fly. This way works every time though, and the engines last longer.

have fun,
-Mike
  ----- Original Message ----- 
  From: colin chariandy 
  To: NSRCA Mailing List 
  Sent: Tuesday, June 06, 2006 10:55 AM
  Subject: [NSRCA-discussion] Break-in procedure for OS140


  Just got a new OS140. I have'nt broken in one for 5 years...what's the best/current practice for break-in?

  Colin.
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