OS 91 engine info

[W. Eddie Batchelor]

Scot
I don't know if you keep old messages or delete them -so I'll copy one here for you.
Nat Penton posted the foollowing info on 10-25-03 :
>Matt I will add additional  info. Have been running the 91FX over two years
>and it will carry my 8+ lb airplanes to the moon. On fuel - was using
>Ritches 20%, now 30%,idles under 1500. Pipe length- 26 to 28" depending on
>which pipe, most power from ES 2 stk(1 9/16 OD), Favorite props 17X10N cut
>to16" and 15.5X12, rpms around 7700. Using Hanno (same as 140RX) backplate
>pump. Can be installed with simple tools and a little ingenuity. O yes 2
>headshims. Stock bearings good for about 30 flts, Boca sealed well over 100,
>leave all seals in place. Provide crankcase cooling for longer bearing life.
>Have not tried 15CC Hatori or MACS but plan to. Headers are from Karl
>Mueller,very nice.

if you start with the 15X10 prop and work up you might be surprised at the power with the longer pipe settings.

Eddie


  ----- Original Message ----- 
  From: Scott Anderson 
  To: discussion at nsrca.org 
  Sent: Saturday, November 01, 2003 8:36 AM
  Subject: Re: OS 91 engine info


  Thank you for the reply, I'm still in the tuning phase also right now with a OS 91 fx and using the Karl Mueller header and a macs pipe (1062), I'm running 25% cool power with a 14x10 and 15x10 prop. 
    ----- Original Message ----- 
    From: Ihncheol Park 
    To: discussion at nsrca.org 
    Sent: Friday, October 31, 2003 10:42 PM
    Subject: RE: OS 91 engine info


    Hi, Scott,

    My 91 SX-H with standard Macs Products' 91FX header and Blue Bird 140 2C pipe (not available in the states anymore) turns APC 15x8 @ 10250 @21.6" from glow plug to first baffle.  Not all tuned yet.  This is with Magnum #1 or Coolpower 25%.  I don't remember which fuel I used when measured this.

    Hope this helps,

    Ihncheol Park
      -----Original Message-----
      From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]On Behalf Of Scott Anderson
      Sent: Thursday, October 30, 2003 4:56 AM
      To: discussion at nsrca.org
      Subject: OS 91 engine info


      Good Morning,

      I see that there was some info being kicked around about the os91 2 stroke engine with props and a head shim, but what is the pipe length to first baffle from glow plug ( straight line). 
      Thanks..

      scott
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