Noob in need of major tuning help

[NooP]

I've got an rs4 nitro mini
os cv .15 still running the hpi exhaust
blue thunder 20% nitro
some glow plug a local hobby store sold me and I'm un aware of the brand.

I have read every tutorial and manual that I can find about tuning the carb. I can start my engine with ease all the time. it idle for days with out a hiccup, but I have one major problem....

When I get up to full throttle my motor seems to flood and die out. Sometimes it does it after 1 full throttle pull and dies on decel and some times it takes a few times before it does so. If I drive it around only going to about half throttle it stays snappy and quick off the line.

This is my first Nitro car. Is it just tuning? or is something else possible wrong. From what I have read, the OS motors are fairly user friendly and easy to tune, but I have spent close to two weeks tuning this thing. and its very unstable for me.

I'm not trying to win championships or anything, i just want to drive the car with out it dying constantly, but ofcourse i still want it to stay fast.

Please ask questions if you need to know a little more. I just want the car to run good and stay running.

--NooP

 

[Diver6127]

You may be running too lean. There may not be enough fuel going into the carb at the higher rpm's. You said that you can idle for days with no prob, good ... so all you have to do is richen up the HSN. Do the adjustments a little at a time and run it around to test it out and let the new settings take effect.

 

[olds97_lss]

By a little, do 1/16 turn on the high speed needle until it will open up without dieing.

 

[NooP]

well, its not dying out at high rpm..... it happens after high rpm one decel are at a stop. Also if it does not die after high rpm, when it gets to a stop, I loose my quick snappy throttle. The car begins to be real slow and sluggish on the low end. Sometimes so bad it dies. After a long hard full throttle accell I find myself quickly tapping the throttle to keep the enging running. I am a noob, but I do not think that's lean. It seems and acts very rich to me. The thing that gets me is that it only acts like this after being at full throttle for longer than a secound. Sometmes, if I'm lucky, I can get a couple quick full throttle snaps and the car continues to run like a dream.

--NooP

 

[olds97_lss]

I think it's lean. After your high speed run, it's starving for fuel. So as soon as you let off the throttle, the inertia of the engine isn't keeping it running any more. Also, it's probably sluggish because your over heating it due to it being lean.

After you run around at low speeds, it cools off and you can open it up again.

Any idea what temps your running?

 

[NooP]

no clue on the temps. I can say that it is hot to the touch of my fingers, but I do not think that helps much.

If you two are saying that its lean, then I'm going to add some fuel to it and give it a try. I will do that and post my results.

After all I am the NooB.

--PooN

 

[olds97_lss]

Since you don't have a temp gun, get one. It's $40 that will save your engines.

I bought mine at radio shack and i won't drive without it. It isn't worth the risk.

Although, after a year and a half of running, you can hear it run hot or cold.

 

[NooP]

well, to be honest with you, I already blew the motor once. The secound day I had it, I was cranking the motor and was not aware that the carb was at WOT and BooM! I snapped the Connecting rod. So I replaced the connecting rod and crank and while I was at it I got a secound set for "just in case."

I dont have 40 lying around right now, but i will put it to the top of my list of things I need to get.

Also, this carb/motor combo is suppose to be relatively easy to tune right? Yesterday I got an OFNA GT LX Pro, and I succesfully tuned that thing in a few hours. Again, I'm not tuning for PEAK RACE HP, i just want the car to be fast and at the same time still be fun to play with.

--NooP

 

[olds97_lss]

I have the OS 15 cv-r(x) in my xxx-nt. I had the same issues you did and i reset to factory settings. I had had it happen right after i cleaned the carb. I had run about 2 gal through the engine and decided to clean everything. So, i took the carb apart and cleaned with alchohol ahd q-tips. I apparently wrote down my needle settings wrong and ended up way lean.

 

[soc123_au]

Sounds too lean on the bottom end, your top sounds OK

 

[SkyMaxx]

Aside from the lean setting that seems to be the consensus, the best advice anyone has given you is to reset to factory presets for the engine. Why? This gives you a baseline to start from. Once at the factory presets, you can tune accordingly.

The symptoms you mention point to a lean setting, but some of your description could also point to an over rich condition. If you know what your needle settings are, at the moment, that is good information to post. Why? It gives those that have the same engine an idea of whether you are running rich or lean based on the factory presets.

So, I'd say set the needles back to presets and tune from there.

 

[NooP]

The settings right now are: HSN 1.5 turns out from close, LSN flush with that light copper nut, and the idle is about 1mm open.

I did start tuning from factory settings, but no matter how I turn it, it dies on decel or at a complete stop after a hard accel and a little bit of hesitation.

But I will say I never tried making it richer from the stock setting. I just assumed that the stock setting is already very rich and only needs to be leaned out a little bit.

I have not had time to touch my car all week, but I will this weekend. I will start richening it up from stock setting and post my results here.

If I haven't said so already, Thanks for all the help.

--NooP

 

[lykan]

Being a new guy to nitro I've had quite the learning experience.

The last few times I took the nitro out it just wasn't up to par. I figured at 1.5 gallons, that I had just been too hard on it being new to tuning and all.

Just for giggle last night before we took it out on a run I reset the needles to factory, and fired it up. It took a minute of adjusting to get it to where it wouldn't die when I hit the throttle (way rich).

Well, a few very small adjustments from the stock setting, and this thing was rippen around pretty good. Judging by the performance I must have really had the needles out of whack. It ran good idled well, and didn't heat up. My good running engine returned.

I have a new policy now, because the tempurature changes are so dramatic here. Before I run, I reset the needles to factory settings. I know for a fact it will start easy (rich) at the factory settings. The it's just a tweak here and there on the HSV and I'm good to go.

I guess what I am saying is that after a few outings, a 1/4 turn here and there on both needles, I had no idea where they actually set. Without a base line to start with, I just got farther and farther out of whack until I was way too lean on the LSV, and way too rich on the HSV.

 

[soc123_au]

Dont assume that the "factory settings" on your engine are set correctly when you get it. I have had a couple of engines over the years that were incorrectly set from new. When I get a new engine I always bottom the screws out & count the turns to see where it is set & check the documents or get on the net to find out what the factory setting is meant to be if I am not sure. If I can't find out I will richen the top at least a turn & the bottom about a 1/4 before I start it. If it wont start I will lean it a bit at a time untill it fires up & then adjust it so it will run, while being rich.
Then tune accordingly once it is run in. A mistake I made when I got started was I assumed all engines had roughly the same needle settings & the first few engines I had all ran really well at around 2 to 2.5 turns out on the top & I never really touched the bottom end. After a few years I started getting serious & got a performance engine (RB) & excitedly put it in & went to the park to run it in. I checked the top end needle & it was 5.5 turns out & I am thinking that is way too rich so thinking I know what I am doing I set it at 3 turns because that should be rich compared to other engines I have had. Well what a disaster, needless to say the engine was toast, & a valuble lesson was learned. In the case of the RB the factory was right & I was wrong but I have had engines that were way too lean from factory & only by checking before starting they didnt suffer the same fate. What I am trying to point out is dont be afraid to go too rich & then come back to the right setting you wont hurt your engine by doing this.
Sorry if I have ranted on a bit much.

 

[NooP]

It was leaner than a motha f*cka! I turned it out and now it rips even faster. My secound gear kicks in now too. It wasn't even kickn before.

any suggestion on tuning secound gear?

--NooP