i have some newbie tuning questions

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Banshee

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i am a complete newb to nitro rc and i dont wanna f- up my engine when i can finally run my truck. so i need you guys's help.

i figured out yesterday where the low speed and high speed needles and idle screw on the carb are. by the way i have an 03 fantom .12 engine (rear exhaust, rotary carb).
my first question- what the hell is lean and rich? i have yet to figure out what that means and i know its very important to know.
also in front of my carb (or more like on the side) there is a little metal thing. i think it is a throttle arm? when i move it from side to side the carb like opens and closes. its real easy to move too, like it would move while I'm using the truck. i dont know if this is good.

now to actual tuning- when i first start the car, i dont know what i should do. i guess if it runs good i should just leave it but i may have to tune it since the atmosphere is different then it was where the guy that had it before lived. the engine manual says to return the setting to factory and start from there. i assume you do this while the engine is running? I'm thinking you turn all needles clockwise (in?) until they stop. then bring them out 3 turns or whatever as the manual says. am i right or can i mess it up like that.

i read the recent thread (i think robh's) on tuning. and i guess it would be helpful but i dont know the basics.

oh yeah this doesn't pertain to tuning but when i try to put my air filter on the carb, the idle screw blocks some of it from going on it. i dont know what to do i think dirt and stuff may get in since its not completely on the carb.

sorry for the long post, but i wanna do this right. i may have more questions later on but for now thats it. thanks alot.
 
Well, where to start? Anyway, "rich" means more fuel. The richer it is running the more fuel it is getting. The oils in the nitro fuel are what lubricate the engine and must be present or the engine burns up. "lean" means less fuel. There is a balance point where you get enough fuel to well lubricate the engine but have it lean enough so you get the power from the engine. The instructions with the R/C should step you through the breaking process. As long as you have not moved the mixture screws it should be where it needs to be to start the breaking. You cannot skimp on this process and try to speed things up by cheating or you will hurt the engine.
As for the air filter, it should fit over the top of the carb enough to seal all the way around. I found on one of mine it was like you say yours is and hit the idle screw. I went to another air filter with a thinner bottom section for around the carb. You should also use a wire tie or small hose clamp to secure the air filter. You don't want to damage the carb by overtightening it but make it snug so the air filter can't just fall off.
I hope this helped some.
 
larry- thanks that cleared the whole rich/lean thing up. also the engine was broken in by the previous owner of the truck so i dont have to do that. edit- i just fixed my air filter so it fits over the carb and clears the idle screw. i just took a dremel and carefully made a small groove in the side of the filter. its still completely intact (the rubber was real thick).

bmoc- yeah i mentioned i read that thread but did not understand it since i did not know even the basics such as what rich and lean are.

any more help would be greatly appreciated, and thanks for the quick replies to you guys.
 
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thanks alot nitro dave those articles are great! i never though to look there.

now i would really like to know about that little thing that i think might be a throttle arm in front of my carb that opens and closes the carb when i move it. what is this and is it supposed to be easy to move?
also if someone can answer my question about how to get back to factory settings if i need to do so.

and another question i have that i just thought of...what does WOT stand for? i am pretty sure it means full throttle but I'm not 100% sure.

I'm really sorry for all the questions but this is really complicated for me and once i get the basics down with your help it will be so much easier.
thanks alot.
 
Banshee-
1. WOT=wide open throttle

2. This isn't meant to belittle you, but are you sure your carb is a rotary one? if it is, how much play is there in the side to side motion?

3. Tell what the manual says are factory settings, and I'll help you get back to those.
 
If the lever on the carb moves clockwise and counter-clockwise you have a rotory carb and yes it should be easy to move. This is what meters how much fuel enters the engine ay a given throttle position when driving. The farther you pull the trottle trigger the more it opens to the point of WOT (wide open thottle oe fuel throttle), like flooring the gas peddle on a real car. At an idle the opening inside the carb should be only about as wide as a peper clip wire or maybe a bit less. The small screw that you had to clear for the air filter adjusts this idle setting. As for breakin, I would suggest that even though it was broken in already, that you turn both mixture screws out about 1/2 to 3/4 turn and go through a tuning process with the fuel you are going to use. If you change fuel types or nitro content you must again tune the engine. Adjustments are common place for even weather conditions but these are generally very minor. All you need to do is be sure of what you are doing before you do it. Don't jump into something with no clue what you should do. Everyone here will be more than happy to help you out if you have questions.

And guys (gals, whatever), give the kid a break with the search and previous thread stuff. He may very well not have a clue what you are talking about without a link and explaination.
Thanks, Larry
 
yeah its a rotary carb. says it on the can the engine came in.
ok i kind of understand now the carb is supposed to be pretty much closed at idle and it opens more and more as you pull the trigger. but, is there supposed to be something connected to that little arm that controls the opening and closing of the carb? theres nothing connected to mine. so i dont see how it could open and close by itself.
if someone has a pic or can take a pic of this area of their truck properly set up, that might help me out alot. i guess it doesn't have to be a xxx-nt (that would help) but it needs to have a rotary carb.

my factory settings as the manual says are-
-3 turns out with HSN
-1.5 turns out with LSN
-idle adjustment set so throttle is about 1 to 1.5mm (I'm guessing how open the carb is?)

it says turning CW (in) leans it, and CCW (out) richens it.

also larry you said to turn the needles like 1/2 turn out when i put the fuel I'm gonna use, but is that from what they are now? shouldnt i go back to factory settings and work from there?

thanks. you guys are being a huge help.
 
can anyone answer my questions (read above post)...this thread kinda died before the rest of my questions were answered.
 
hey, i should tell you that the throttle arm that opens and closes the carb should be attached to a servo arm. If ya want send me an "aol instant message" and i can send you a pic of what mine looks like.
 

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