Hi All, Does anyone have a problem keeping their Nemesis running at idle? I need to have the idle up pretty hight to keep the thing running. Can someone give me their setup that has no problems. Basically I want to be able to start me Nemesis without it taking off on me and I would like to be able to hit the brakes without killing the motor. Has anyone messed with the Throttle trim on their Airtronics to help? I have tried adjusting the carb stop, but it seems that I have to keep a pretty good gap to keep the truck running. Any help is appreciated.

Have you tried adjusting your LSN? Sounds as though you might be alittle rich if it dies when you hit the brakes. As for anyone elses settings, this in theory would/should work but the difference in outside temps, humidy, and pressure will make in nearly impossible for my settings to work for your area. Sorry I can't help more. If take off is good and it doesn't bog then go I would start with the LSN, if it does sputter on take off then try your HSN.

I do have that problem. It is a pain in the a.. In fact, it is so annoying to have the engine shut down every time I hit the brakes when it has reached operating temperature, that I am buying a new engine.
Tuning this engine is very, very cumbersome; said by me, said by my LHS (which sells a lot of CENs). There is no way you can set this engine up to have more than 2 laps in a track without it shutting down.
If you manage to do set it right, let me know but I truly wish you luck.
I am just buying a .30 or .32 engine; Andrew Smolnik, CENs racer, uses a .28 anyway and kicks butt.

I think you have the HSP and the LSN mixed up there. If it sputters and bogs from a stop it is the LSN.


A rule of thumb I use is i clear out the engine and then let it idle until I hear the idle drop. a good setting for the LSN is a drop in idle in about 9 seconds. If it drops earlier it is a little rich on bottom if it takes longer it is lean on bottom.

NEVER use you radio trim to set your idle. Use the idle screw on the carb.
NEVER tune a cold engine.

Adjust idle AFTER you have the HSN ans LSN set..

Start out with the engine at tempature. get the HSN set then work on getting the LSN set, then adjust your idle. The gap doesn't really matter as long as it is idling.

Make sure you have a clean air filter. A dirty one will change you needle settings

i had the same problems that all of you are having , its the lsn. i got so frustraded that i took the carb off and put compressed air through it. this is what i did, i removed the carb, closed the hsn all the way in, closed the lsn all the way in now with a can or a compessor blow air through the fuel line opening and slowly open the lsn. you will notice that it will go past the flush mark by i would say 2 to 3 turns befor you hear air coming out. i found that if its flush there is no fuel coming in. then i marked that setting and did the same with the hsn and found it to be at 4 to 5 turns out from flush. now the truck idles with a gap at 2 to 3 mm.
hope this helps.

William,
First of all, thanks for your patience and your suggestions. I also own a CT4-S and do not have these problems.
-What do you mean by"clear out the engine"?
-By "hear the idle drop" you mean that when you push the throttle and then let it go, the engine will be revving down slowly until it gets to idle? and once it reaches idle, it should shut down after 9 seconds or so, if you do not give it gas?
-Do you refer to 'rich in the bottom' to the LSN being too unscrewed? too out?

I'll try all your suggestions and look forward to your comments on the above. If I can't make this thing behave, I'll definitely get rid of it; I even bought a new carb thinking that was the problem -it wasn't. CEN really needs to work on this engine.
Thanks also for the air filter tip; didn't know that.
Alex

Jombo,
the gap you talk about... are you refering to a gap between the LSN screw and the screw housing? or the gap in the venturi that is created by the barrell opening?

So now all works great for you? no shutting down even if you give it full gas, then full stop, then full gas, then full stop, and so on as you would on a track? if so, you are a genius.

Sorry to hear all your problems abonnet and skarecrow!!
My Settings are with a OS 8 plug and Crazy nut head. Flush or 0,5 in from flush on the LSN 3,5 to 3/1/4 out on the HSN. All I can say it never stops and temps are great maybe a little high at the end of the tank. My gap is 1,5-2 mm.
I can run my genesis at full throttle then hit the brakes all day long without that my engine stalls. I sure sounds like you have the lsn to lean so start from there, also don't tune the engine before you have at least run half a tank or more. If you tune it before you will not have a good tune at the end of the tank it will get very hot (half tank leaning issue)

I think Losmosis meant that the idle should go down after 9 seconds not die. So if you run your truck at full throttle and hit full break your idle should be a little high for about 9 seconds then go down to a nice low idle but not to low so it dies.

Good luck guys

yes the gap is the throttle barrel stop, the lsn is at 1 to 1-1/2 mm of the brass showing and the hsn is at 4 to 4-1/2 out. the truck after its primed (2 pulls) it starts on one pull. after setting them to this you will fiddle with the hsn so it hits all three speeds( well at least for me) while all the tires are off the ground (hold the rollbar handle and with the truck off the ground floor it then hit the breaks). if it still stalls just adj the barrel idle screw a little at a time. from a stand still the truck will bog a little but now it should idle all day long.btw my temps never went over 210deg. and now i have another prob, the front diff cup broke doing donuts in the lawn but had a blast doing it.

jadda / jombo,

I have my LSN screw OUT about 1/2 a turn from flush ...the more 'out' the LSN screw is, the more rich it is? and the more 'in from flush' the more lean it is? just like with the HSN?

I appreciate your help very much.

A-

Thanks for the help all. I will try what you suggest but I need to repair my rear shocks first. I blew them apart trying to do a backflip. I am going to get the roto-start, I am tired of the blisters on my fingers from starting this thing. I will update the thread when i get this fixed.

What do you mean by!QUOT!clear out the engine!QUOT!?

Pick up the truck and rev it up to clear out the engine so it is not loaded up with fuel. Hit the brakes and then begin to count. the idle will drop off some but not die as Jadda describes.



-Do you refer to 'rich in the bottom' to the LSN being too unscrewed? too out? Unscrewed, counter clockwise, fat, rich...

LSN and HSN work the same way. the only difference is that the HSN adjusts mainly higher RMPS. it does effect lower rpm's in a small amount. LSN effects low RPM's...

When you lean out, turn clockwise, or tighten you take fuel away from the engine it it replaced by air....

When you fatten, turn counter clockwise, or screw out you add fuel to the engine and take away air.....

With more fuel also means more oil, this is why when you engine is too rich it stalls and doesn't run correctly.

With less fuel you engine runs hotter and in extreme cases runs out of fuel at high speeds.

You are looking for a good balance between lean and rich. most run their engines on the rich side to make the engine last longer.

You can use the listed above needle setting as a starting point if you choose to but be very careful you do not over heat your engine.

I race all over the U.S. and have rarely had me engine to run the same from one place to another.

Make very small adjustments at a time with an engine that is at temperature.

Think of the screw you are turning as an hour hand on a clock and make 1 hour adjustments at a time, run the car a little to allow the change to take place then readjust as needed..

This engine is a really good reliable engine once tuned properly.....

That you all for the input with his problem.

I have mine on the settings cen says, HSN 3 1/2 turns out and LSN 1 1/2 turns out. I can stop with out killing it, idles perfect. Idles about 1-2mm from closed. Take off your air filter and put the brakes out and see where it closes? I have that at 1-2mm from closed.

William, thanks again for the advice; I'll try all of the suggestions posted and will get back to you with whatever result I get.

Thanks all!

A-

For All:

The way William described fixing this problem is SPOT ON! I was going to respond but there is nothing left to say but re-read what he has stated and follow his advice. He is one of our top drivers with this truck and knows this engine very well.

Good luck and have fun with your CEN Racing products!