chapi93

I have an Exceed Madfire with the .28 engine and It's new to me as is the world of RC. I've broke it in right with 3 to 4 tanks of fuel. I have a question about the glow starter. When first starting it, how do i know when to pull the starter off the plug because it seems to stall when i pull it off after about 20 to 30 seconds. Should i leave it on longer? And i also have a question about the air screws. I live in Maine about 350 feet above sea level. The factory settings for the upper air screw was set to 3 turns out an the lower at 2 1/2. What would be a decent setting and how should the engine run at a good setting?

(MRC) Scotty!

Once the engine is started you should be able to pull it off almost immediately. With one or two exceptions. If the engine has not been started for a while, or if the weather is extremely cold..

If you are leaving it on for 30 seconds and it is still dieing, then the tune is off or the idle is too low..

Do the pinch test to see if LSN is set correct. pinch fuel line as close to engine as possible. It should take right at 3 seconds for the idle to raise due to lack of fuel (known as lean condition) If it takes longer or if it happens nearly immediately then tune is off.. If it takes 3 seconds for idle to come up then set the Idle gap wider to allow for more air to enter engine.

Once you can get it to run and stay running, you can get it dialed.. I say dialed because race tuning on an engine should be done after engine is warmed up..

chapi93

Ok i'll try the LSN test. By the way, what does it mean and your saying the idle gap wider. Does that mean i'm turning in the idle screw to bring up the idle?

(MRC) Scotty!

Yes.. Never adjust idle with the radio.. it'll only cause it ot bog or die whne brakes are applied..

chapi93

k thanks. What does LSN stand for? I'm not sure the sound of normal idle, is it kinda high because i'm used to hearing the idle of a four wheeler or a dirt bike which seems to me is kinda low.

(MRC) Scotty!

LSN = Low Speed Needle.. LSN is usually in the end of the slide on the carb..
HSN= High Speed Needle.. HSN is just above where the fule line get plugged in..

IS this engine new? WHat kind of engine is it? Has proper break-in been done on it? If this is your first Nitro engine, go to your Local Hobby store or race track and ask for help. Most guys will be happy to help out, and if you don't get help your just going to trash this engine.. IF it's not too late.

The idle will be higher than a 4-wheeler.. but not as much as you might think..

Chris_RC

As a reference, your idle is too high if your tires spin if you take them off the ground.

chapi93

It's a EX<div><span class="Apple-style-span" style="font-family: arial, helvetica; font-size: medium; color: rgb(255, 255, 255); "><table width="100%" border="0" cellpadding="2" cellspacing="0" id="Table2"> <tbody> <tr class="g1" style="background-color: rgb(219, 219, 219); color: rgb(0, 0, 0); font-family: Arial, Helvetica, sans-serif; font-size: 12px; text-transform: capitalize; text-decoration: none; "> <td class="g1" align="left" style="background-color: rgb(219, 219, 219); color: rgb(0, 0, 0); font-family: Arial, Helvetica, sans-serif; font-size: 12px; text-transform: capitalize; text-decoration: none; ">0.28 Cubic Inch. (4.6 Cc)</td> </tr> </tbody></table></span>How will i know if i did trash it haha</div>

(MRC) Scotty!

It is hard to say. How long have you had it?

chapi93

I've had it for two weeks and idled two tanks through it at their factory settings (which is upper air at 3 out and the lower air at 2 1/2 out and only had it on the road once for about one tank. I just had it out on a stand today trying to dial it in keeping the idle just enough so the tires won't spin like the other guy mentioned. It bogs when i give it throttle then comes out of it. I adjust little by little but can't seem to get a happy medium.

Chris_RC

You want to lean the LSN to take away the low end bog you are experiencing if there is alot of smoke coming out of the pipe when it bogs. I adjust LSN first but that is just me. You will want to do at least 6 tanks for breakin before you go Wide Open Throttle (WOT). Leaning the LSN will make the idle higher you you would want to lower the idle screw.

Try the pinch test as mentioned and adjust with LSN. All the idle goes is adjust the carb opening, it does not adjust fuel mixture while the LSN does and adjusts performance with idling and acceleration.

(MRC) Scotty!

I agree with eveyrthign chris said..

Idlin 2 tanks of fuel through an engine does not complete break-in.. There are alot of dynamics that need to be taken into consideration.. What your doing when breaking-in and engine is getting all the surfaces to mate up as best as possible, and get rid of any foriegn material left from machining.. Since you are just now past tank 3 do this.. Stop trying to tune it..

Now reset all needles to factory settings. Turn the HSN in 1 hour, think of the hands on a clock and how far the hour hand moves for one hour, in other words 1/12 of a turn.. When you do this run another tank through the engine. Repeat this process of leaning 1 hour per tank of fuel until you use about 3/4 of a gallon of fuel.. Keep in mind you need to allow engine to fully cool off between runs.. If you get half a tank through it and it dies let it sit until cool completly before refiring.. This is known as the heat cycle method and is considered the best way to break in an engine, allow for excellent engine life and awesome power.. If engine is hard to start check glow plug, and make sure fuel is at the engine.. Do't just grind on it to get it to start.. Very hard on a Cold engine.

When you get through the 3/4-1 of a gallon of fuel then your ready to start "Race Tuning". This is how I race tune, and everyone is different.. Fire engine up and slowly drive it around until engine is warmed up.. Now if your going to race, take it to your track, and take it down the longest straight with no jumps or turns or that distance in a parking lot, But you need to mark it because lengths are deseving... Lean out the HSN and hour and repeat until you no longer see a performance gain or a very minimal gain. Now richen the HSN 1 hour from it's current setting and it should be good. Now let it idle down.. Since the LSN is set at factory rich setting you will want to lean it out now.. Do it the same way, 1 hour at a time, except your looking for it to pull hard and evenly from a stand still up about 30 feet.. Lean LSN until the engine no longer pulls harder up to the mid range area.. When it no longer revs quicker then richen back up 1-2 hours and do the pinch test.. If set right the idle will start coming up at about the 2-3 second mark. Any longer and it it is still rich.. If it idles up more quickly then it is too lean. Adjust by hour which ever way until pinch test falls with-in the 2-3 second range. Now you shoudl be ready to turn some laps, or go BASHING!

Do none of the listed stuff in RED until Break-in is complete. A Proper break-in on a nitro motor will take about 8-12 hours.. This will allow engine to get up to temp and cool back off completely after every cycling.. If you have one us a Heat gun to help heat engine before starting.. makes starting easier.. A high powered Hair Dryer works well too..

(MRC) Scotty!

Hey Chapi, I was wondering how you came out on your engine? Get it tuned right? Runnning better at least?

chapi93

Hey Scotty. It seems to run alot smoother now even from take off. I give it full throttle real quick and it takes right off. I actually have a couple questions about minor things (hopefully minor haha). When i get it up to a little over half throttle and hold it for a couple seconds it will crackle a bit, or sputter a couple times but doesnt seem to lose power and the other thing is it takes off from the start like i said smoothly but i dont know if it's at its full potential. Is it the clutch or just cause i'm new to this or is it how they are. I think i'm at a good spot with the LSN so...

PS. Ordered a RB Innovations Cylone type "S" cold air intake filter. Any good?<br type="_moz" />

Chris_RC

Sounds like your HSN is lean when your sputter at full throttle.

I would just stick to the stock filter and buy 2-3 foams, so you cna switch them out easily.