YS 91SR sounds odd when loaded

[creightoncarr]

I've got a YS 91SR in my N9 with a SB-19. The engine sounds a little odd to me when its loaded, kind of a gurgling sound. It's a new engine and only has about two gallons through it. 1st gallon the heli was flown pretty mildly. The 2nd gallon was a little harder and with a TJ RevMax at 1820 and 1900. The engine is still running pretty rich (about 1.2 turns out on all three needles - maybe slightly less on the idle) with head temps of about 150 degrees. This is my first YS engine so I'm not used to the sounds its making and what they are telling me. You can hear the engine in this video: http://media.putfile.com/Creighton---N9---10-28-07

It sounds good until the 1:00 minute mark and then you can hear the "gurgling" for lack of a better term. You can really hear it at 1:38 and on. Is it possible this is just a combination of running very rich with the limiter engaged? Next time out I'm going to starting leaning more but I wanted to get some ideas if anyone had some. I can't complain about the power, despite the sound and how rich its running the power is still there.

[Lusk]

I would normally run the engine in and have my needle settings right before using the governor with a new engine. You maybe just too rich with your needle settings.

[conrod]

What gear ratio, and fuel are u using?

[Long Nguyen K.]

I've got a YS 91SR in my N9 with a SB-19. The engine sounds a little odd to me when its loaded, kind of a gurgling sound. It's a new engine and only has about two gallons through it. 1st gallon the heli was flown pretty mildly. The 2nd gallon was a little harder and with a TJ RevMax at 1820 and 1900. The engine is still running pretty rich (about 1.2 turns out on all three needles - maybe slightly less on the idle) with head temps of about 150 degrees. This is my first YS engine so I'm not used to the sounds its making and what they are telling me. You can hear the engine in this video: http://media.putfile.com/Creighton---N9---10-28-07

It sounds good until the 1:00 minute mark and then you can hear the "gurgling" for lack of a better term. You can really hear it at 1:38 and on. Is it possible this is just a combination of running very rich with the limiter engaged? Next time out I'm going to starting leaning more but I wanted to get some ideas if anyone had some. I can't complain about the power, despite the sound and how rich its running the power is still there.

1.2 turns out at the middle needle is kind of too lean IMO. I find mine running best at:

- 0.8 turn out at idle
- 1.4 turns out at middle
- 0.9 turn out at high

The tunning is at 105ft above the sea level.

The "gurgling" sound could come from the extra fuel when the engine moves to the high range. Open up the mid needle to 1.5 and close the high needle to 1.0 or 1.1 and see how it goes.