Motor Tuning Question....
11-21-2005, 03:07 PM
#1
Tech Master
Thread Starter
Motor Tuning Question....
I have Sirio 3 port 12 and have tried another carburator with no luck...
When I get the engine hot and run it wide open for a couple seconds it seems to 'stick' at half speed then idle down. I have redone the linkages and they are going to neutral fine. I don't think the issue is there becuase even if I hit the brake its still rev'ing.
Any ideas? Thanks!
When I get the engine hot and run it wide open for a couple seconds it seems to 'stick' at half speed then idle down. I have redone the linkages and they are going to neutral fine. I don't think the issue is there becuase even if I hit the brake its still rev'ing.
Any ideas? Thanks!
11-21-2005, 03:16 PM
#2
hard to say from the given info.. what temps are you getting?
sounds like its too lean and detonating..
sounds like its too lean and detonating..
11-21-2005, 05:12 PM
#4
Engine losing power as it gets higher in its rpm would indicate that its running too lean (lean bogging)....richen it out a bit.
Cheers
Cheers
11-22-2005, 07:52 AM
#5
Tech Master
Thread Starter
Thank you for your help!
11-25-2005, 12:28 AM
#7
did you put on the O-ring between the carburator and the body? 
11-25-2005, 12:48 AM
#8
Tech Fanatic
Exception to every rule!
I agree with everything that was said above, but believe it or not, being excessively rich on the Low speed needle can also lead to an engine running on. If rich on the bottom end, rpm decreases & engine will stall. To combat this, some people turn up the idle on the carby (screw it in). As you come off the throttle, the engine still has a belly full of fuel and due to the idle screw (on the carby) keeping the throttle slightly more open than usual, this causes the eingine to run on.
The solution would be to return the carby to factory settings, adjust your trim on the radio, set your gap (throttle opening) to 0.5mm with the idle screw. Then you start tuning at the top (High speed needle), then the bottom (low speed needle) for response off the line, then adjust the idle accordingly.
p.s. I was told this by the Australian 1/8th scale champion last weekend,and he also demonstrated it to me. I had the exact same problem with my N12LL3.
Im not saying that this is definately the problem with yours, but its worth a try.
Hope this solves your problem!
The solution would be to return the carby to factory settings, adjust your trim on the radio, set your gap (throttle opening) to 0.5mm with the idle screw. Then you start tuning at the top (High speed needle), then the bottom (low speed needle) for response off the line, then adjust the idle accordingly.
p.s. I was told this by the Australian 1/8th scale champion last weekend,and he also demonstrated it to me. I had the exact same problem with my N12LL3.
Im not saying that this is definately the problem with yours, but its worth a try.
Hope this solves your problem!
Last edited by Rody; 11-25-2005 at 01:13 AM.
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