Magnum 120RFS low speed needle setting
03-18-2005, 06:57 AM
#1
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Magnum 120RFS low speed needle setting
Can someone, please, pretty please tell me the amount of turns 'out' on the factory setting on the low speed needle. I adjusted mine too much both ways and now can't even get the engine to start. Please help.
thanks,
thanks,
03-18-2005, 08:10 AM
#2
RE: Magnum 120RFS low speed needle setting
I can't tell you the exact amount because there is none listed in my instructions, but here is a procedure that came with Super Tigre engine instructions 25-30 years ago. It will work for anything.
1. Close the low end needle. Open the high speed needle the normal amount.
2. Put a T-pin in the carb throat and close the carb so it holds the pin. This sets the opening at a small amount.
3. Hook up a 12" or so length of fuel tubing to the carb and blow through it while listening for air flow through the carb.
4. With the low end needle closed, you should get no air flow. Open the low needle until you just hear a hiss. This is your initial setting.
If your engine is new, don't expect it to idle really well until it is broken in. A ringed engine, unlike an ABC type, takes a good bit of time and fuel to seat the ring. Until then, expect a lot of oil through the drain tube back to the inlet. For a big engine, I would say it will take 2 gallons of fuel, maybe more, to fully break-in. Don't think you are going to get a "tick-over" idle immediately.
Be sure to use a 4-stroke type plug. Thunderbolt plugs are OK, but the OS Type F is the best.
Run fuel with castor, especially for break-in (first 2 gallons). After that you can go all synthetic if you like.
1. Close the low end needle. Open the high speed needle the normal amount.
2. Put a T-pin in the carb throat and close the carb so it holds the pin. This sets the opening at a small amount.
3. Hook up a 12" or so length of fuel tubing to the carb and blow through it while listening for air flow through the carb.
4. With the low end needle closed, you should get no air flow. Open the low needle until you just hear a hiss. This is your initial setting.
If your engine is new, don't expect it to idle really well until it is broken in. A ringed engine, unlike an ABC type, takes a good bit of time and fuel to seat the ring. Until then, expect a lot of oil through the drain tube back to the inlet. For a big engine, I would say it will take 2 gallons of fuel, maybe more, to fully break-in. Don't think you are going to get a "tick-over" idle immediately.
Be sure to use a 4-stroke type plug. Thunderbolt plugs are OK, but the OS Type F is the best.
Run fuel with castor, especially for break-in (first 2 gallons). After that you can go all synthetic if you like.
03-18-2005, 10:41 AM
#3
Senior Member
RE: Magnum 120RFS low speed needle setting
This will work for most engines. Set it up for the high speed end first by having the low speed needle intentionally open more than you think it should be. After the high speed is adjusted for the desired speed, bring the engine back to idle and slowly close the low speed needle until the engine reaches its maximum idle speed (the engine will speed up as the mixture approaches the ideal) then open the low speed a slight amount, about 1/8 turn or less. Readjust for the high speed setting and all should be ready to fly.
