OS 46FX Max adjustment
09-21-2006, 02:45 PM
#1
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OS 46FX Max adjustment
OS engine adjustments ???
Hi guys!
I always start my OS 46FX Max with 2 full turn from a closed needle valve. When started ( Full throttle), I slowly close the needle valve to get the highest RPM. Then, I trim and take it back to idle. Problem is, when I try to take it back to full throttle, the engine cuts off. The engine seems to hate fast throttle rate changes. Is it because there's too much air or too much nitro getting in? Any Solutions? Advice from pros?
Thanks from all replies in advance.
Oh! And I know... I 'm quite a beginner!
MArc!
Hi guys!
I always start my OS 46FX Max with 2 full turn from a closed needle valve. When started ( Full throttle), I slowly close the needle valve to get the highest RPM. Then, I trim and take it back to idle. Problem is, when I try to take it back to full throttle, the engine cuts off. The engine seems to hate fast throttle rate changes. Is it because there's too much air or too much nitro getting in? Any Solutions? Advice from pros?
Thanks from all replies in advance.
Oh! And I know... I 'm quite a beginner!
MArc!
09-21-2006, 04:31 PM
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RE: OS 46FX Max adjustment
There are two needles, and the one your adjusting for top RPM is the high speed needle.
The other needle, the low speed needle takes care of the lower rpm settting such as idle and throttling. The low speed needle is located in the throttel barrel and you need a small screwdriver to reach it.
A. If the engine just dies when you blip the throttle, the low speed needle is to lean and need to be unscrewed a bit. 1/8 of a turn is good adjustment intervall.
B. If the engine sags down, sputter and maybe quit, or slowly gain rpm, the low speed needle is to rich and need to be closed a bit, again, work with turning the needle 1/8 of a circle.
Once the low speed needle is dialed in for good idle and throttle respons there's seldom need to touch it again.
The other needle, the low speed needle takes care of the lower rpm settting such as idle and throttling. The low speed needle is located in the throttel barrel and you need a small screwdriver to reach it.
A. If the engine just dies when you blip the throttle, the low speed needle is to lean and need to be unscrewed a bit. 1/8 of a turn is good adjustment intervall.
B. If the engine sags down, sputter and maybe quit, or slowly gain rpm, the low speed needle is to rich and need to be closed a bit, again, work with turning the needle 1/8 of a circle.
Once the low speed needle is dialed in for good idle and throttle respons there's seldom need to touch it again.
09-21-2006, 04:38 PM
#3
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RE: OS 46FX Max adjustment
Mark,
I'd start by backing the main needle off a hair from absolute max RPM.
Then you need to adjust the low speed mixture, it's the screw in the center of the throttle arm.
It's hard to tell from the description if it's rich or lean at idle but I'd guess rich. The good thing is that you don't really have to know if it's rich or lean, you're going to adjust it by experimentation. Make a change, test, make a change, test, etc. Keep track of the total adjustments you make so you can get back to where you started.
So try turning the low speed needle in about a half a turn. Start it up and let the engine run for a bit until it quits stumbling, throttle back, throttle up and see if it helped. Kill the engine, try another half turn and repeat. Any improvement? If it's better but still not right, keep going. If it's worse, back your changes out and try a half turn in the other direction.
When you get it close, try smaller adjustments. Find the area where it works best and set it in the center of that area.
My FX took quite a bit of tweaking but now it transitions instantly. On mine I had to have the low speed screw almost all the way in. But I've had others that were a couple of turns out.
Good luck,
Dave
I'd start by backing the main needle off a hair from absolute max RPM.
Then you need to adjust the low speed mixture, it's the screw in the center of the throttle arm.
It's hard to tell from the description if it's rich or lean at idle but I'd guess rich. The good thing is that you don't really have to know if it's rich or lean, you're going to adjust it by experimentation. Make a change, test, make a change, test, etc. Keep track of the total adjustments you make so you can get back to where you started.
So try turning the low speed needle in about a half a turn. Start it up and let the engine run for a bit until it quits stumbling, throttle back, throttle up and see if it helped. Kill the engine, try another half turn and repeat. Any improvement? If it's better but still not right, keep going. If it's worse, back your changes out and try a half turn in the other direction.
When you get it close, try smaller adjustments. Find the area where it works best and set it in the center of that area.
My FX took quite a bit of tweaking but now it transitions instantly. On mine I had to have the low speed screw almost all the way in. But I've had others that were a couple of turns out.
Good luck,
Dave
09-22-2006, 08:58 AM
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RE: OS 46FX Max adjustment
It's also not necessary to reset the needle everytime you start it. Once you find a setting that works you rarely have to reset the needles. You might have to tweak the high needle a few clicks as the air temperature changes but that's generally all you need to do.
