[NSRCA-discussion] OS 140RX rough and inconsistent idle

[Ed Miller]

Thanks to all that responded. Engine has had a Boca stainless steel sealed rear bearing since new and right now I cannot feel any play in it. I'm leaning towards some kind of leak in the carb area, although the nose of the plane is dry.  Head bolts are tight.  I'll be taking it apart today and hopefully I'll find the problem. 
Ed M.  
  ----- Original Message ----- 
  From: Keith Hoard 
  To: NSRCA Mailing List 
  Sent: Monday, June 26, 2006 9:27 AM
  Subject: Re: [NSRCA-discussion] OS 140RX rough and inconsistent idle


  I'll second that. . . . check your bearings and put in a set of stainless. . .


  On 6/26/06, mwaustin54 at cox.net <mwaustin54 at cox.net> wrote: 
    You might check your bearings. My OS 140 did this after 50 or so flights. New bearings solved the problem. I also run the Mentor head and like the transition. 

    Mike A.
    ---- Ed Miller <edbon85 at charter.net> wrote:
    > Have an OS 140RX that has developed a rough and inconsistent idle. Engine
    > runs perfectly except for idle. It has a Mintor head with either an OS F or 
    > K&B 1L in center plug and an OS A5 in the angled plug position, a Perf Spec
    > AAC piston/liner assembly and a Boca sealed SS rear bearing. I have the head
    > mounted with angled plug towards the front or carb side of engine. Fuel is 
    > S&W 20 nitro, 16 synthetic and 2 castor. Engine has 7 gallons of fuel run
    > through it. Prop is an APC 15.75 x 11 3 blade by Dave Lockhart.  The lowest
    > I can get the idle before it quits is 1900 ~ 2000 rpm and it is rough, 
    > sounds like it is firing every other revolution. Idle mixture screw is
    > working, I can richen idle to point where engine will barely transition from
    > being rich and I can lean mixture so the transition is fine but engine slows 
    > at idle like it is too rich. While it is slowing with either the idle
    > mixture screw lean or rich, engine is rough, again like it often fires every
    > other revolution at times. I used to be able to reliably idle this engine at 
    > 1300 rpm. I have a second OS 140RX set up exactly the same except it doesn't
    > have the AAC piston/liner and it runs/idles perfectly. Tried cleaning the
    > carb/spray bar with no change. I once had a Super Tiger that exhibited 
    > similar characteristics due to a worn out con rod.  Is it possible the con
    > rod on this OS could cause this issue ?? Any suggestions will be greatly
    > appreciated.
    > Ed M.
    > _______________________________________________ 
    > NSRCA-discussion mailing list
    > NSRCA-discussion at lists.nsrca.org
    > http://lists.nsrca.org/mailman/listinfo/nsrca-discussion 

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  -- 

  Keith Hoard
  Collierville, TN
  khoard at gmail.com




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