Still need some help tuning my nitro rustler

[yfzracer450]

Hey everyone, so I bought a nitro rustler brand new and I immediately had problems with trying to tune it. One day it would act like it's great then the next it would run like crap. But anyway I bought the os carb for it and thought everything would be great. It runs really good up and down the road but it had like a pinging noise when I left off throttle at full so I richened up.

Took it out into the yard and it seems like it's running really good. It's idling pretty good when I checked the temp it was like 230 with the body on and mind you I'm in Florida where it's 92° right now. But after about 1/2 tank or so acts like it's starving for fuel. I left off throttle and kinda blip and tank it easy for a second then it's back to ripping. Is it just cause the tank is 1/2 empty and it struggles for a 2nd to pick up fuel? I do made some sharp turns back and forth in the yard and I don't really have a lot of space to really open it up.

Also when I shut it off I have like 5 or 6 drips of oily brown liquid come out of exhaust tip. I know some is normal. Is that amount normal? It was A LOT more until I realized I had accidentally messed up the mixture screw so I put it back to factory setting and it got a lot better. I'm running sidewinder fuel backyard basher 20%nitro 16%oil

 

[WoodiE]

@yfzracer450 take a look at our thread Nitro Tuning Tips and Tuning Flow Chart

 

[yfzracer450]

Thanks. So maybe I have it to rich? But I richen it out today because the other day it was doing the same thing before I richen it so maybe I just need to find that sweet spot. It has a nice blue cloud of smoke all the way through and it idles and sits still no problem for a over a minute. I know on the factory carb you do the pinch test. Is that still true for the os carb?

 

[Thvts_Nvte]

I've really only been tinkering with Nitro for about a year now. And I'm still learning, and I've tuned bike carbs, multi carb setups ITB's, rebuilt god knows how many 2 stroke dirt bike carbs. Nitro though, is killing me some days they can be finnicky.

So, I'm running that same fuel currently, my LHS had it at $20 for a gallon so I figured why not? I think the oil content is too high, plus I was eating through plugs for a while when I first switched over to it. I find that I'm chasing a good tune for the better half of the first tank once I'm up to temp. And when I'm up to temp I can't seem to find an idle (this is likely my traxxas carb I think) so maybe try some different fuel once you burn through this stuff? The oil out of your exhaust seems normal, maybe a bit more than my Revo - but if I'm running it rich and hard for a while it'll put a puddle on the ground, which is way too rich. But normal for this example tune. When I was breaking it in that tune was super rich and would leave a massive puddle.

If you're sounding like you're starting to starve of fuel, maybe you are. Any chance your tank isn't holding a vacuum?

Pinch test is still valid, although that's not how I turn mine off. I just plug the pipe so I've never paid much attention to my tune from that way.

Make sure to do adjustments slowly. Do an adjustment. Take it for a lap. Bring it back let it sit for a second before touching it again. Or else you'll find yourself chasing a tune and getting ahead of the adjustments you've made and finding yourself in a never ending cycle with the tune.

 

[Lostinthewoods86]

New to this as well and dove into nitro first (less than 6 month’s experience ). Two brand new nitros, one Traxxas and one Hpi. Started having tune hunting issues kinda as described on both, finally the Traxxas wouldn’t start and was spittting out fuel between head and block, tightened head back down (which was surprisingly loose but what did I know) and the Hpi we bought later did the same thing, i caught it before it got to the no start.


If nothing else it doesn’t cost anything to make sure the head is tight

Edit to add I also swapped to os 11k carb on the Traxxas before I found the issue on mine

 

[rceverywhere]

i had many years of ski doo, motorcross lawn mowers, then years of 1 scale cars even did drag racing. when it comes to tuning a glow engine .. forget what you know and learn from the guide writen up! i thought i knew what i was doing and my first nitro engine lasted four gallons. after that you have no choice to listen to experience or give up nitro. my next nitro engine ran threw over ten gallons and i lost count due to getting many more to burn the gallon. i still have it and only took it out to put a bigger one in its place.
dont worry about drips from the exhaust ... unless you have none. those things should make a big mess all over your car, bench and shelf, a rubber cap helps when in storage. they realy need to sound like they can barely run when could then will always start to run better after a good few laps wide open, ricker is safer than too lean, never forget all lubrication to the engine comes from the fuel

 

[gandalfnz]

Oil dripping is normal, especially with that much oil in the fuel. Nothing to worry about, I also use 16% oil content on my nitro's and they run great. Gives you a bit more headroom if running lean, so you don't damage the motor.

If its pinging after WOT you are lean. Richen the HSN a bit more then retry.
Be aware that when richening HSN you will need to adjust LSN as well.

If you see bubbles in fuel lines check for air leaks, fuel tank, lines....etc.

Good luck!

 

[Zerksies]

I hope you are aware that outside tempurature and humidity effects the tune of one of these engines drastically. I can't stand tuning by tempurature. I've had cold engines run very lean. I find it better to learn how to tune by ear. A properly runnig engine has a destintive sound.

 

[cbaker65]

If it struggles on take offs especially after it sits a minute ,then that would be your Lsn. needle
an not the Hsn.!
When you try to tune the Hsn. needle all the time to take care of that low end bog ,it is only
going to further lean out the top end an your not going to accomplish nothing!

Set your Hsn. until your engine is happy at full WOT ,then check for low end bog ,
if it is sluggish when you stab the throttle from take off ,the the Lsn. needs to be
leaned in ,only make about a 1/16 of a turn at a time until you get the slug out!..

 

[easy rider]

small turns on an os carb results in big changes. Lots of great advice. No need to add to it. Learn the flow chart and follow bakers advice