...venturi size...

[Bootlegger]

 Mornin fellow's,
  I have a Ringmaster that is powered by an OS 25 FP, with a .250 venturi, I am lookin for suggestions as to what size venturi will be better.
  The fuel is Powermaster 5% with 22% oil (half & half) a Thunderbolt long plug w/idlebar and a 9x5 APC prop line length is 58' eyelet to eyelet.
  Probably around 10,200 or there about  R P M range...
  Thanks again Sparkey for this site...

[Bill Little]

Hi Gil,

What do you want it to do different?  Have you tried it?  Not trying to be a smart alec, just not sure of the question.............

Bill <><

[Steve Holt]

The FP25 on my ARF Streak has the same venturi, an OS needle valve assembly, and the OS 2030 muffler.  Tank is a 3 oz Hayes clunk on muffler pressure.  On a 9X4 APC prop I set about 12,500 rpm on the ground.  Works well here in Tucson on 60' lines.  Fuel is 10% nito, 22% oil (half castor and half syn.).  I have used the same set-up on a Ringmaster with good results.  If it is too fast on 60' lines, try 63'.
Steve