Noob Nitro Tuning Questions

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Metallicats33

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Okay after flying/driving Electric Rc for some time now. And also Driving my brother in-law's Nitro Losi over the past year, I Decided to get my own Nitro.
I have the XTM XT2 w/ .247

I have run into a few problems that I thought I would try and get some feed back on. I'm going to list the problem and if Any, what I did to correct it. Please let me know if what I did was right or if I'm doing something wrong.

1. Engine Dies at Full Throttle (Too lean?)
correction: Richen High speed needle
2. Engine Dies from Stop - Full throttle
correction: Richen low speed needle
3. Engine wont idle more than 3-5 seconds
correction: adjusted idle stop screw
4. Engine Revs high for 5-10 seconds after coming to a complete stop, then idles down
Correction: ??? still scratchin my head
5. Engine sounds rough at idle and has low acceleration
correction: ??? Still scratchin my head

Also I'm not trying to blow my first Nitro car up. How rich is too rich? I know running it lean will cause it to overheat, but will running it rich cause any damage?

Thanks for any input and please excuse my noob questions but I really want to get this right..
 
technically there is no such thing as running too rich..running too rich will only cause the engine to be more sluggish than it is now. and also running rich may cause you to burn out a glow plug or 2...if your engine is sounding rough at idle, is it more of a gurgling rough? or how exactly would you explain the sound of it at idle? my guess would be if it sounds rough and has next to no acceleration from stop i would lean the low speed needle just a hair and see what that does for ya. good luck
 
my guess would be if it sounds rough and has next to no acceleration from stop

Yes, thats exactly right. As far as rough, It sounds like it wants to die. I will lean out the low speed needle today and see if that helps. thanks for the info.

Also, is it normal that I have to adjust the throttle trim a bit to get it started?
 
Also, is it normal that I have to adjust the throttle trim a bit to get it started?

Ya, with a new engine. But once it gets broken in it should start with normal setting
 
Ya, with a new engine. But once it gets broken in it should start with normal setting

So Idle set screw? or LSN? If my high Side is real rich would that also cause a hard start? I don't have to adjust the trim too much just a bit, If i don't it runs for a second before it dies.

And when is an engine considered Fully broken in? I ran almost a quart in it (6 tanks) using the heat cycle method and half a quart tunning... One more tank will make two quarts through the engine so far....
 
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if hsn is rich it wont cause starting problems as the motor isnt being revved while starting...low speed being rich will cause starting issues. and being a new motor everything is sooo tight in these engines, so the idle will gradually come up on its own as things break in inside the motor...so you shouldnt have to worry bout idle issues then
 
Thanks for all the input everyone. The noob questions keep pouring in though:) I tried to learn on my own for the last week but I decided that I should seek some input.

Last question (for now) How long should I run a engine before I let it cool down?

My brother in-law says As long as I got fuel to put in it, keep it running.... But He also blew his stock motor in a little over 2 gallons of fuel:hehe:
 
get a temp gun it will help a great deal with tuning. Also once tuned you can do random temp checks and if you see a need to let it cool down then by al means do it. I have ran 5 consecutive tanks out of my revo with no cool down because the temps where good.
 
I do have a temp gun, Highest it ever got was 230* but that was after 4-5 WOT passes. I read that thats normal. It usualy runs around 190 - 210 depending on how I drive it. So I guess that would mean my HSN is ok, So time to focus on LSN and Idle screw?....
 
yeah your temps are a little on the low side to be honest...you could lean the hsn another 1/8th turn...but you more than likely need to focus on the lsn and idle set screws right now and get her dialed right in...you can run these things as long as you want as long as the temps dont get crazy on you, and your batteries dont die in the transmitter or reciever and your good...
 
yeah your temps are a little on the low side to be honest...you could lean the hsn another 1/8th turn...but you more than likely need to focus on the lsn and idle set screws right now and get her dialed right in...you can run these things as long as you want as long as the temps dont get crazy on you, and your batteries dont die in the transmitter or reciever and your good...

Good to know, thanks for all the help. I'm going to fiddle around with it in about an hour or so...
 
Those are good temps for that engine, i would not mess with the HSN if top speed is good.
Lean the LSN until it takes about 8 seconds for the idle to drop down after a wide open pass. Then adjust your idle screw as necessary. After that the engine should be able to idle for at least 8 seconds without loading up, if not lean it a bit more.
Those engines have al. carbs with no insulating sleeve on the carb, if you start to get around 250F it will vaporlock on you.
 
Okay, I think I got it:)

I leaned out the LSN and have good acceleration with visible smoke at idle and a steady trail while running. Engine will idle over a min. I didn't have my temp gun today but I used the "spit test" took about 2 seconnds to simmer and about 3-5 seconds to simmer off. I still have to give it a slight bump on the throttle to start it after it has cooled down, but after it's warm it starts up first pull almost every time.

should be able to idle for at least 8 seconds without loading up, if not lean it a bit more.

Loading up? I'm sorry I'm not familiar with that term, what does that mean?
 
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loading up is when too much fuel goes into the motor at idle and it bogs down
 
One more quick question, My brother in-law said it's okay to use Brake cleaner in place of nitro car cleaner... Is brake cleaner safe on a nitro car? Specifically the engine area around the glow plug (always got lots of dirt there)
 
Yes, but electrical cleaner is a little less caustic and does the job just as well.
 
good to know, Thanks for the info.
 
Just one point.
On how long to run ya car before allowing to cool down.
I have never run more than 2 tanks of fuel before i let i cool down(not saying it will not run longer).
But after 2 tanks of running then cooling down gives me a chance to give it the once over (loose nuts screws etc):D
 

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