Nitrolizer
Well-Known Member
- Joined
- Jul 25, 2006
- Messages
- 45
Ok, here is a problem I usally have on all my nitro-racing engines (boats & cars).
When I'm tuning in the needles, I usally set the high-speed needle first. It may take a few testruns to find the best setting, but no problems so far.
Then it's time for the idle-needle. I usally make sure to start with a setting that is sure to be too rich, rather than being too lean. Then I just lean it until the throttle response (from idle to full throttle) gets quick and stable. But here is the problem:
Usally, I can run on mid to high-throttle, then go to idle for just a second, and if I then crank it again there is an instant response. BUT.... If I let my model run on idle for a litte longer (let's say 15 secs or more), then when I suddenly crank it the respons is very slow, and I can hear the engine running in "4-cycle" for just half a sec or so, just before it goes back into normal 2-cycling and revs up to its peak.
My questions:
1. Why does this happen only when I let the engine run on idle for a longer time, and not when running in idle for just a second before I rev it up again?
2. Can this be fixed with the idle-needle? If I set the idle-needle too lean, my engines most often get unstable when running on idle. If I then richen it a little, I get stable idling but the problem I described above occurs instead (slower reving after idling for a longer period of time).
I have this problem on all my boat and car engines, basically. Old as new.
By the way, I'm usally running 25% nitro with 15-20% oil (the oil mixing usally differs a bit depending on where I buy the fuel).
Any suggestions? I'm sure most of you have experienced this yourself. Anyone who has managed to get the needle just perfect, without experiencing any of these problems? Or do you usally just tune it for secure idling as a first priority, and then try to not run in idle for too long (as a way of avoiding slow throttle responses)?
All suggestions are appreciated. Thanks.
When I'm tuning in the needles, I usally set the high-speed needle first. It may take a few testruns to find the best setting, but no problems so far.
Then it's time for the idle-needle. I usally make sure to start with a setting that is sure to be too rich, rather than being too lean. Then I just lean it until the throttle response (from idle to full throttle) gets quick and stable. But here is the problem:
Usally, I can run on mid to high-throttle, then go to idle for just a second, and if I then crank it again there is an instant response. BUT.... If I let my model run on idle for a litte longer (let's say 15 secs or more), then when I suddenly crank it the respons is very slow, and I can hear the engine running in "4-cycle" for just half a sec or so, just before it goes back into normal 2-cycling and revs up to its peak.
My questions:
1. Why does this happen only when I let the engine run on idle for a longer time, and not when running in idle for just a second before I rev it up again?
2. Can this be fixed with the idle-needle? If I set the idle-needle too lean, my engines most often get unstable when running on idle. If I then richen it a little, I get stable idling but the problem I described above occurs instead (slower reving after idling for a longer period of time).
I have this problem on all my boat and car engines, basically. Old as new.
By the way, I'm usally running 25% nitro with 15-20% oil (the oil mixing usally differs a bit depending on where I buy the fuel).
Any suggestions? I'm sure most of you have experienced this yourself. Anyone who has managed to get the needle just perfect, without experiencing any of these problems? Or do you usally just tune it for secure idling as a first priority, and then try to not run in idle for too long (as a way of avoiding slow throttle responses)?
All suggestions are appreciated. Thanks.