.46 FX won't stop running
07-31-2004, 07:34 PM
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.46 FX won't stop running
On 7-28-2004 I purchased a new .46 FX. This is replacing an OS .46 SF that I have ran for 12 years. The exchange of the engines only took a few minutes and even the throttle linkage adjustment looked good. The break in and idle adjustment went 'by the book' as all of my OS engines have (.40 FP, .46FX(1st), .46AX, .91FS).
I have a problem with a new .46FX. This engine will not die when the throttle is closed. It will idle very slowly for 30 to 60sec. I have checked all screws for thightness, reset the linkage and used 'end point adjustments' on my computer radio and adjusted the throttle stop on the carb (hobby shop owner said to) to no avail. I also adjusted the idle mix to the lean side and this will let the engine die, but I think that the engine will die in the air (fails pinch test). The engine has a total of 25 oz. of Byron Premium Sport Standard fuel, with 15% nitro and 16% oil, through it. I am using an idle bar glow plug and a 11x6 prop.
I usually do not have problems with the OS engines. But this one has stumped me.
What can I try next?
Paul
I have a problem with a new .46FX. This engine will not die when the throttle is closed. It will idle very slowly for 30 to 60sec. I have checked all screws for thightness, reset the linkage and used 'end point adjustments' on my computer radio and adjusted the throttle stop on the carb (hobby shop owner said to) to no avail. I also adjusted the idle mix to the lean side and this will let the engine die, but I think that the engine will die in the air (fails pinch test). The engine has a total of 25 oz. of Byron Premium Sport Standard fuel, with 15% nitro and 16% oil, through it. I am using an idle bar glow plug and a 11x6 prop.
I usually do not have problems with the OS engines. But this one has stumped me.
What can I try next?
Paul
08-02-2004, 11:49 AM
#2
My Feedback: (11)
RE: .46 FX won't stop running
First off, 25 ounces of fuel is hardly anything. Your engine would be nowhere near "broken" in.
We'd expect a bit more running time on the engine and then see how it goes.
As far as cutting off is concerned, you'll need to see what RPM you're running with which prop. Usually people try to idle the engine too slowly. This upsets the balance between the high-speed and low-speed needles.
Start out with a very rich idle mixture. Start the engine at part throttle and get the high-speed mixture set first. Then retard the throttle and get the low-speed mixture set. You want a low idle, but acceleration is also a factor. Any idle RPM below 2,700-2,800 RPM would be considered good.
Make sure the carb's seated fully into the crankcase. A bit of air leakage there could be a cause.
Don't worry about a lot of things until you have a few hours' worth of running on the engine. It won't be fully broken-in until you have those few hours.
We'd expect a bit more running time on the engine and then see how it goes.
As far as cutting off is concerned, you'll need to see what RPM you're running with which prop. Usually people try to idle the engine too slowly. This upsets the balance between the high-speed and low-speed needles.
Start out with a very rich idle mixture. Start the engine at part throttle and get the high-speed mixture set first. Then retard the throttle and get the low-speed mixture set. You want a low idle, but acceleration is also a factor. Any idle RPM below 2,700-2,800 RPM would be considered good.
Make sure the carb's seated fully into the crankcase. A bit of air leakage there could be a cause.
Don't worry about a lot of things until you have a few hours' worth of running on the engine. It won't be fully broken-in until you have those few hours.
