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2.5 needle settings

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bashaholic

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Anybody have any ideas as to why my 2.5r won't run on factory settings? I've removed both needles and flushed fuel through through the carb, so I don't think its debris blocking fuel flow. If I keep it at factory settings I'm smokin hot in no time. It makes it kind of hard to tune when you don't know where you're supposed to be starting from. I ended up at 5.25 turns out on HSN and 1.25 out from flush on LSN. It ran ok (but not great) for awhile. It eventually heated up to about 280-290 even at these settings. This motor does'nt seem to run good unless I'm at these temps (still getting a decent amount of smoke). I talked to Traxxas and they were'nt much help, they said it should'nt even run at these settings! :shrug: :hammer: :shrug:
 
Below 270 is good to go. In your case, I will suggest check for leaks. Seal the backplate and carb ATV silicon.
 
MyJeep said:
Below 270 is good to go. In your case, I will suggest check for leaks. Seal the backplate and carb ATV silicon.
Click to expand...
Thats RTV Silicone.

What has been done to the 2.5R so far? What plug? any Mods? More info !!
 
I've ran either a Traxxas 3232 or an os LC3 without much difference. I've got a stock pipe and run 20% o'donnel. Outside temps were about 40f.
 
If you're past your break in, you should start with the HSN at 3 1/2 turns out, then set the LSN flush with the inner ring. NOT the outer ring that the linkage is connected to, but the INNER ring. At that point it should start and run, but might need some additional tweaking.
 
I've got about a gallon& a half through it and I cannot run at those settings for some reason. It ran hot at break-in and has always acted like this.
 
are you sure your not mistaking half turns with full turns
 
I agree with Traxxas. It shouldn't even run at those settings. If it did run at all like that, the temp would barely reach 150 unless there's a burr or something clogging the fuel intakes.
What you might also want to do is completely remove the needle and the seat, and blow a blast of air through it to make sure it's totally clear.
If you've had that problem since it was new, and you've already spoken to their tech support, I suggest you call them again for warranty service. It seems to me that there's a major problem there that needs to be corrected by them.
If you know anyone else with a Revo that runs right, you might want to switch carbs with him just for a test. I think it's a carb problem, and swapping them out would isolate it.
Guys at the track have done that before just to de-bug odd issues.
 
FWIW, I was using O'Donnell 20% in my Revo and it ran like crap. It heated up quickly and wouldn't stay running. I switched to Top Fuel, and I've not had a problem since. I think I got an old bottle or something of the O'Donnell stuff.
 
I have had the same problem with mine the other day i was running it and it got to 360 degrees and steam was coming from the head. i richened it up and got the temp down but it didn't run as well. i ran about 2 tanks that day try to tune it and gave up. so i put it back to factory setting and awaiting good weather to test it. I have about a gallon of fuel through it and run a trx 3232 plug. I'm new at this so i'm comfused about what performace gain i should notice from the tuneing and how many high speed passed is enough to clean old setting. any help would be great, So ROLEX if your listening help please on what i should do next.
 
Why are you asking me? What do I know? I just make stuff up as I go along. :shrug:

Okay, now that you're about at factory settings, start it and just let it idle.
If you gave it a lot of trim to keep it idling, let it warm up, then start to adjust your idle screw as you lower the trim. It needs to idle fast enough to keep running smoothly, but not enough to chatter the clutches or make it want to creep forward.
Keep checking the temp as it idles until it stabilizes, and doesn't rise any more. Let me know what the temp is. Very often, it's a LSN setting that makes them overheat, and adjusting the HSN won't help that problem.
It should idle between 180 and 210. Getting it there is a LSN adjustment. If it's too hot, you need to richen the LSN a little, and you might have to raise your idle screw. Keep doing little blips on the trigger while you adjust, so the carb can 'accept' the adjustments. Each time you make a change, let it keep idling for another minute or so while you keep checking the temps.
When the temp is right, put the car on the ground and just drive it from a stop to about half throttle a few times to clear it out. Check the temps again.
Drive it, and see how it performs, and take temp reads after a few high speed runs, and let me know what you get.
 
Well Rolex you seem to be the master at tuning i've read alot of your posts ans it seems you know the most. when you say give it trim do you mean on the throttle trim on the transmitor or by squezzing the throttle?
 
Any reference to 'trim' is the adjustment on the radio. When you set your idle screw, it should be done with the trim knob all the way off, so you KNOW that the idle screw is stopping it from closing farther. Any trim needed, after proper adjustment, is just to make starting easier, and to allow it to warm up at a faster idle.
 
what is the best way to gauage the opening is says it is suppose to be about 1mm is that true? clockwise is in or out?
 
Clockwise is the way the hands turn on a clock......oops, doesn't work with a digital one.
Well, if you remember what old clocks are like, the hands turn to the right, or IN with the idle screw to raise it. (the farther the screw moves IN, the farther it holds the carb open at idle)
1 to 2mm is an approximation of the opening. The idle and the LSN work as a team. When you adjust the LSN, you usually have to reset the idle speed.
 
Be carefull about too much adjustment on the throttle trim, you could mess up the Opti-drive and eat reverse. If you make much of an adjustment to the trim, you will need to reset the Opti-drive, read the manual.
 
thanks i'll try that tomorrow morning before i have to go to work so i'll let you know what i get.
 

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