I just recently got into the RCnitro car market and bought a traxxas rustler 2.5 - i followed all the break in instructions through tanks 1-5 and started adjusting the high speed needle and low speed needles as well as idle. I thought Ihad them both tuned fairly well until my after about 15min of run time my truck starts bogging out and slowing down. Its hard to get it to accelerate after this point and will sometimes stall if i try to punch the gas too fast. The first 15min or so are fine. I dont think i'm running too lean because i do see a trail of blue smoke everytime i accelerate however my engine starts to smoke as well.

Is this an overheating problem? Any idea how to solve it.

Also any suggestions on a way to "reset" the high speed and low speed adjustment needles? Like tightening them all the way up and starting over or loosing them all the way out?

I'm not sure how to fix this issue or what the issue actually is, I really enjoy the car and want to take good care of it to have it for a while so any help would be greatly appreciated

Hello and sorry for your troubles.

Iwould definetly invest in a temp probe. It is an absolut neccessity to run nitro. The OFNA or other units can be head for $25 dollars.

Reset all the needles to the the factory settings. Should be in the Manual, if not go to the Traxxas site.

Pull the plug and check,if it's very clean or discolored like a reddish brown it may have been running hot or lean or both.

If so go out another full turn on the high speed needle. Don't even touch the idle or low speed jet till the truck is fully broken in.

Ihope you are using Traxxas or similar nitro fuel and not some cheap brand, because the amount of oil can make a difference.


Check to make sure that the brake isn't dragging. Body off operate the throttle and brake (car not running) to see if brake is disengaged when throttle is on. Check for free running of all wheels and drivetrain

Once you havd done all this run car, not hard, just moderate and keep checking the head temps. If you can't get the temp probe spit on the head if it bubbles off very quickly it's too hot.

If it runs okay then keep braking it in per Traxxas manual, keep checking head, body off. If temps hold to 220 to 230 then put body on and again run moderate,check temps. Keep doing this and run harder ,if temps okay then you can lean out but keep checking for temps. Leaning it out should not go more than 1/8 to 1/4 turn at a time.

If this doesn't work contact Traxxas, they are great customer service,


Hope this helps

Jim




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Factory for the HSN is 4 turns open.  Turn the needle all the way closed (clockwise), but do not over tighten it.  Then back it out (counter-clockwise) 4 turns.  Factory for the LSN is flush with the end of the slide.  The manual does not give a factory setting for the idle, but most engines are set to a 1mm opening looking in the carb.  Check page 24 of the Rustler manual for factory settings, including a little drawing showing what "flush" means, and that section of the manual in general for tuning info.  Here is a link to the manual if you do not have it handy.

http://www.traxxas.com/products/nitr...9nr_manual.pdf

Good luck.

Bryan

Thanks Both for all your help and tips, I really should pick up a temp probe because it's definitely running TOO hot after that 15min's of running for some reason. I was checking around some posts and I saw somebody mention resealing the engine - taking it off the carb and using a sealent to fill any places where air might be getting in - do you think this could be my problem???<div>
</div><div>Its so bizarre and like i said I'm new to RC Nitro market but it blows blue smoke like its running rich but stalls and the engine smokes like its running too lean, how could t show signs of both. </div><div>
</div><div>I still have the traxxas manual - basically like my bible to the car but thank you for the link. </div><div>
</div><div>I'm going to  to try what jim said after I reset the needles to factory settings and go from there. The brake is not engaged - it's almost too loose because its really hard to stop the truck, even with the idle low enough so the car isn't inching forward. I finished the break in period completely before any of these problems arose. Step for step and tank for tank. </div><div>
</div><div>Thanks again guys</div>

Before you take apart the engine, check for air leaks, the hoses, the seal at top of tank. Not a bad idea to change the hoses. I would do that before I take apart the engine.



Jim

The seal at the top of the gas tank? I just bought the car about a week ago - is it possible i already need to replace the fuel lines?

It sounds silly, but it is a good habit to always push the lid shut when you fill the fuel tank.  If the tank is not getting good pressure, the fuel flow will be diminished, and the engine can run lean.  Pushing the lid every time as a habit helps ensure the O ring seats and seals the tank.

Are there bubbles in your fuel line?  If so, that is a good indication of inadequate pressure, an obstruction somewhere blocking/plugging the flow or an air leak somewhere in the fuel system.