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Engines Plugs Mufflers Fuel > OS 91 temp range?
 
 
tittelba
Senior Heliman
Location: Bolingbrook, IL

Hi, I'm having a hell-of-a-time getting my OS 91 properly tuned. The needles seem to be very sensitive in that one-click on the high speed needle seems to make it too rich or too lean. I think I'm close to having my needles set but I'm not sure of temp the OS 91 should be at. It's at ~ 170 F immediately after landing from a hover.

Questions:
1) should I lean it out a little and raise the temp?
2) are the needles on the OS91 real sensitive or might I have some blockage?

Thanks,
Tom

www.baltimoreboyz.us
05-07-2002 Over year old.
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Al Magaloff
rrMaster
Location: 12,199 Posts- Enough Time Wasted. See Ya!

Tom, what fuel?
05-08-2002 Over year old.
 
 
tittelba
Senior Heliman
Location: Bolingbrook, IL

Coolpower 15% with 3% Klotz added

www.baltimoreboyz.us
05-08-2002 Over year old.
HOMEPAGE  
 
 
Al Magaloff
rrMaster
Location: 12,199 Posts- Enough Time Wasted. See Ya!

I should have asked what muffler. KSJ ? Try the head shim. It will give the needle some range.
05-08-2002 Over year old.
 
 
Al Magaloff
rrMaster
Location: 12,199 Posts- Enough Time Wasted. See Ya!

Also, try a colder plug. It will retard the timing somewhat.
05-08-2002 Over year old.
 
 
rickc
Elite Veteran
Location: Creve Coeur IL. (Peoria Area)

That temp is fine for the .91, I would not be afraid of running it at a temp of up to 220 at all. Buy using 15% fuel and adding oil you are lowering the nitro % even more. The lower the nitro the fussier the needle valve adjustment can be. I would try a gallon of YS 20/20 blend fuel or even some 30%. As the other post has asked you, what muffler are you using? Running a .61 muffler will not let the engine perform to its ability.

Rick
05-08-2002 Over year old.
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tittelba
Senior Heliman
Location: Bolingbrook, IL

Thanks for the help.

I'm running it with a Hatori 2-piece made for the .91. I'll try changing the fuel and plug.

www.baltimoreboyz.us
05-08-2002 Over year old.
HOMEPAGE  
 
 
tittelba
Senior Heliman
Location: Bolingbrook, IL

I was able to mess with it again tonight and still no luck (Haven't changed the fuel or plug temp yet though). I noticed that from idle to midrange the smoke trail changes from light to heavy. When I open the idle needle, to try to richen it up, it always stalls…even with a slow increase in throttle…if I lean the idle screw even 3 degrees the smoke trail becomes very light again.

I also noticed while hovering that the smoke trail will change from light to heavy without moving the throttle. What would cause this? I’m thinking maybe some debris in the needle ports or maybe pin hole in my fuel line. I’ll pick-up some 20/20 this weekend (if I can find any).

Thanks,
Tom

www.baltimoreboyz.us
05-09-2002 Over year old.
HOMEPAGE  
 
 
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Engines Plugs Mufflers Fuel > OS 91 temp range?
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