skrez

My Feedback: (15)

Hi all,
I have a os 48 surpass that I ran on a test stand last night. The carb is the air bleed type, so my question is how do you adjust the low idle with this type of carb?
Regards,
Frank

w8ye

My Feedback: (16)

The idle mixture needle on the air bleed type carbs works backwards because it controls air and nut fuel.

Typically though these engines still run a little rich with the tip of the air bleed screw completely away from the air bleed hole.

The OS 52 or Magnum/ASP 52/61 carb will directly replace the air bleed carb if you are interested..

skrez

My Feedback: (15)

Thanks for your reply. Would it hurt any to take that air bleed screw completly out?
Frank

w8ye

My Feedback: (16)

Try it and see but I doubt it would change it much

Here's the Magnum carb
http://www.hobbypeople.net/gallery/280010.asp

Also the OS 52 head is the same except the glow plug is recessed down in the head 4mm. The extension part of the plug is completely inside the combustion chamber. Gives you 300 rpm. Otherwise the heads are the same.

speedster 1919

My Feedback: (3)

Frank OS spent millions of dollars r&d engines. That was a special size air bleed hole and is meant to be pluged about half way with screw. A 1/4 turn in either direction is enough usally. Don't take screw out and don't drill hole bigger. If you do that then your HS has to make up for LS and idle will have to be faster. Your asking for dead sticks after a few minutes into flight.