YS 61AR LS Problem...

[Karl G. Mueller]

Larry,

Did you ever try running a different fuel? "Wildcat" fuel seems to be using
a heavier oil than most other fuels. I ran into problems with it on an other
Y.S. engine myself. Very inconsistent idle and often quitting on downlines.
It seems that the very narrow fuel passages in the Y.S. carbs don't like a 
fuel with a thick oil and higher percentage as well. I also noticed that the
exhaust residue did have a darker look to it then with other fuels.

Karl G. Mueller
kgamueller at rogers.com



----- Original Message ----- 
  From: Larry N Lisa 
  To: NSRCA 
  Sent: Saturday, May 08, 2004 11:47 AM
  Subject: YS 61AR LS Problem...


  I know this was a recent thread, but my PC had crashed and lost them...This engine hasn't been ran in a while and was purchased used. History unknown.

  Dead-Stick on Stall-Turns. I suspect that this is happening due to a seemingly minor idle problem on the ground. Seemingly because the engine never quite on the ground, just the RPM falls off real low.

  Here is some data:

  1. Wildcat Fuel 15% with 18% all Synthetic oil
  2. Prop - APC 12x11N
  3. Max RPM - 10,300
  4. Adjusted to run max at 10,000 (1/4 turn back from max).
  5. Pipe set at 17" from glow to highest point on Hatori Pipe.
  6. Carb gasket and all regulator parts and seals are brand new.
  7. No Leaks (verified fuel tank pressure at 5psi for 5 minutes with no drop in pressure.
  8. Regulator screw is adjusted flush with body.
  9. Glow Plug is OS #8 and was replaced, no change on ground and same result on Stall Turn.
  10. Check valve appears to be operating properly based on my method of testing.
  11. Good tank pressure after running the engine (Actual measurement not taken).

  The exhaust seems a bit darker than I'm use to indicating possibly running too lean. Could be just cleaning out the internals on the first few runs. Transitioning from idle to full throttle seems very good. However, when going from full throttle to idle it seems to drop off to under 2,000 rpm and at times reads at 1,500 to 1,700 rpm for a moment. After about 10 seconds it seems to jump back up to about 2,400 rpm and then can idle reliably from then on. 

  I suspect that the engine is quitting once it goes back to idle initially with the RPM dropping off too low.

  Thanks,

  Larry Diamond
  NSRCA 3083
  AMA CD 5024
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