please help!

[tone87]

I just bought a brand new aftershock limited edition and have had nothing but problems. I followed the break-in procedures, but the engine is acting really weird. With LSN and HSN at factory settings its ok just really sluggish. Then When I lean the HSN out to where its performing better it will take take off good, but then when i get goin pretty good and left off the engine keeps reving. The throttle is closed when it does this. Sometimes I can throttle it a few times and it will come back down and other times it revs up really high and I have to put my fingers over the exhaust to kill it. Like I said if I richen it up a lot it doesn't do it but then its so rich its almost un drivable. I know the throttle isn't sticking open. I don't know what to do this has me baffled. I hope it wasn't a big waste of money. I would REALLY appreciate any help I can get.

 

[neobart]

You need to tune your low speed needle. It's probably set way to rich and as a result your high speed needle is set to lean to compensate, which is what gives you that high idle when you let of the throttle.

Look down the carb throat and make sure the idle gap is around 1-1.5mm. You may need to lean the lsn slightly to get it to start after this. A good way to test the lsn setting, is to get the engine warm and then pinch the fuel line about an inch from the carb. If it dies right af the bat without changing revs, then the lsn is too lean. If it takes a loong time to die and raises the idle a lot, it's to rich. Ideally it should take between 3-5 seconds for it to die, and the revs should only go up a little.

You may need to go back between tuning the HSN and LSN, but once you have the LSN set, it should mostly only be necessary to tune the HSN.

 

[olds97_lss]

Would be a good idea to give these a read:
http://home.comcast.net/~98gmarquee/pics/misc/ParisRacingEngineTuningTechTips.pdf
http://www.rchobbies.org/cars_eng-tuning.htm

On a side note, I have an aftershock that I bought new. My fuel filter o-ring was cut/sticking out of the filter when I took it out of the box. I didn't realize it until after I tried running it and it ran horrible.

Then after I got that fixed and got it running, I noticed fuel leaking out around the LSN (low speed needle) and it was tuning very erratic. So I tore the engine and carb apart to seal it. I put some associated green slime on the o-rings on the HSN and LSN, then RTV'd the carb neck and back plate really well.

Night and day difference on tune.

Sometimes "new" sucks as much as "used".

 

[tone87]

Hey thanx for the help I had my local hobby shop order some of that associated slime and I picked up some of that copper rtv so I'm gonna seal it up and see what happens.

 

[tone87]

well first off I blew in a hose running to the carb and brushed soapy water around the base of the carb and around the HSN an LSN. I didn't find any leaks, but I went ahead and siliconed the backplate and carb neck. I also checked the fuel tank and it was also leak free(tryed new fuel lines too). I let it sit for two days so the silicone could cure and then I set both the LSN and HSN back to factory settings. I started it and let it warm up, then took it for a couple passes. After that I pinched the fuel line to check the LSN and it revved up really high and after about three seconds it shut off. I A lot higher than it should. It seems like no matter how much I lean the LSN it still revs to high when I pinch the fuel line. I drove it and it was real doggy, it didn't want to move unless I gave it full throttle. I leaned the HSN out a little more than and 8th of a turn. It ran a little better so I leaned it a little more and it took off hard, but when I let off it did the same thing it was doing before. Its pretty powerful and it accelerates good, but it hard to enjoy when it keeps revving you let of the throttle. Does anybody got anymore ideas?

 

[olds97_lss]

You may be too lean on the LSN. Does the idle go down when you adjust the idle screw? If not, then your probably too lean on the LSN.

 

[RC Addict]

Sounds like the carb is sticking. A good throttle return spring would not be a bad idea. Like Bryan said, it is VERY easy to get these mills overly lean. Too rich and they bog, so most people get too over zealous in leaning them out. Check that your carb spacing is 1mm when not running. Check your carb to insure it isn't binding. Check your fuel lines and tank for air leaks. Also, if Losi is still routing the fuel filter right next to the head re-route it. That one change made a HUGE difference with my LST.

 

[Scrogg]

Also watch the header, very prone to cracking. Reduce the idle gap, and retune the LSN from there. Acceleration comes from the LSN. Top speed comes from the HSN.
Check your fuel tank as well. Sometimes the primer buttons leak.

 

[tone87]

I all ready removed the primer and rerouted the fue line. Gonna mess with it again tomarrow and see what happens.

thanx for the tips.

 

[tone87]

Today I put some associated slime on the needle orings and then I ran two tanks through it. It runs better but someting is still not right. The onwer of my local hs doesn't seem to care or wanna help. I dont know why it screams when the fuel line is pinched. I know that means its to rich but no matter how much I lean the lsn out It still does it. The gap at idle is about 1mm-1.5mm. Could there still be an air leak somewhere? I also think I need new clutch shoes because the clutch bell is discolored like it got to hot. Which shoes should I use?

 

[bigjay]

They all rev up when you pinch the fuel line.

 

[tone87]

It doesn't just rev up a little it screams. Like if you would pick it up and hold it full throttle with the wheels off the ground. Thats how high it revs.

 

[neobart]

Way to rich on the LSN then. Lean it little by little, and lower the idle screw accordingly as the idle will go up when you do this.

 

[Scrogg]

Your idle gap is too big. Reduce it down. Tune it around the idle screw, not the other way around. Definitely lean the LSN too.

 

[MIKERUSSO]

well first off I blew in a hose running to the carb and brushed soapy water around the base of the carb and around the HSN an LSN. I didn't find any leaks, but I went ahead and siliconed the backplate and carb neck. I also checked the fuel tank and it was also leak free(tryed new fuel lines too). I let it sit for two days so the silicone could cure and then I set both the LSN and HSN back to factory settings. I started it and let it warm up, then took it for a couple passes. After that I pinched the fuel line to check the LSN and it revved up really high and after about three seconds it shut off. I A lot higher than it should. It seems like no matter how much I lean the LSN it still revs to high when I pinch the fuel line. I drove it and it was real doggy, it didn't want to move unless I gave it full throttle. I leaned the HSN out a little more than and 8th of a turn. It ran a little better so I leaned it a little more and it took off hard, but when I let off it did the same thing it was doing before. Its pretty powerful and it accelerates good, but it hard to enjoy when it keeps revving you let of the throttle. Does anybody got anymore ideas?[/QUOTE

TAKE OFF THE GAS TANK AND REMOVE THE PRIMER SET-UP ON IT GET AN CAP COVER AND SILICONE IT WHERE THE PRIMER USED TO BE, PUT A ZIP TIE OVER IT JUST TO BE SAFE. IT SOUNDS TO ME LIKE IT IS AN AIR LEAK CAUSING YOUR ENGINE TO RUN LEAN...MOST LIKELY IT IS THE PRIMER IN THE GAS TANK...POOR DESIGN IT SHOULD WORK

 

[tone87]

I already removed the primer. I think I'm just gonna get that LRP .28 and throw that .26 in the garbage. I hate to swap it out without getting hardly any use out of it but I'm done messing with it.

 

[86toy]

I already removed the primer. I think I'm just gonna get that LRP .28 and throw that .26 in the garbage. I hate to swap it out without getting hardly any use out of it but I'm done messing with it.

i had the same problem with me aftershock.. the problem is the carb is junk on those engines i bought this carb http://www.horizonhobby.com/Products/Default.aspx?ProdID=DYNP5316
it bolts right on and makes a world of difference. i had my aftershock out today and ran 4 tanks of fuel through it with just a little minor tuning when first starting it. don't throw your engine away just yet.. also check e-bay you may be able to find it a little cheaper

 

[tone87]

hey thats a heck of a lot cheaper than a 180 dollar engine I think I'll give it a try. thanx

 

[86toy]

let me know how you make out

 

[durwank]

It must be a different engine than the Mach .26 that came with my LST. That was a very good engine. Sorry to hear about you having so much trouble with yours though. Nitro trucks are generally a lot of fun but they can be a major PITA too.