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help me tune a friends truck
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t-maxxracer32
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help me tune a friends truck - 02.14.2010, 08:37 PM

wutup guys

so im trying to retune a freinds slayer for him and i cant seem to get it right.

it will usually start up quick and idle fine but if i try and give it gas then it dies out. (hsn is set to stock 4 turns open)

I figured maybe it just needed a good warmup. so it let it idle for 4-5 minutes till the motor was above warm but still when i try and give it any type of gas it dies out

i tried messing with the hsn opening and closing it at 1/8 incriments but it isnt helping much as i dont know exactly what it needs

is it so rich that gas is flowing in and cutting it out or is it too lean where its getting no gas?

I never was amazing with gas trucks but have had my fare share, so if anyone has tips then id be happy to hearem

thanks
   
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magman
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02.14.2010, 09:05 PM

Try leaning out the lsn a bit first


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t-maxxracer32
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02.15.2010, 12:30 AM

I have tried messing with the needle but it doesnt really do much?

maybe i just need to have more patience with it or something.

I ran out of gas today so maybe tomorrow i can give it another try
   
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George16
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02.15.2010, 01:22 AM

Start all your setting at stock then go from there.


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t-maxxracer32
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02.15.2010, 01:31 AM

they all are set to stock...
   
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squeeforever
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02.15.2010, 02:25 AM

Check the pinch when its hot and see if it has any compression. Try the airfilter too...
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t-maxxracer32
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02.15.2010, 05:30 AM

what does that mean.... check the pinch?

and I cleaned the airfilter right before testing because it was horribly dirty.
   
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George16
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02.15.2010, 05:49 AM

Once you get it running and warmed up, pinch the fuel line, count how many seconds before the engines shuts off. Longer than 4 seconds, the LSN is rich. Shorter than 3 seconds, the engine is lean. The LSN is set if the engine dies after about 3 seconds of pinching. Before the engine shuts off, it should rev up a bit too.

Before you do all these, check and make sure the idle gap opening is set between .7-1mm (about the thickness of a credit card or drivers license).


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squeeforever
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02.15.2010, 06:50 AM

Quote:
Originally Posted by George16 View Post
Once you get it running and warmed up, pinch the fuel line, count how many seconds before the engines shuts off. Longer than 4 seconds, the LSN is rich. Shorter than 3 seconds, the engine is lean. The LSN is set if the engine dies after about 3 seconds of pinching. Before the engine shuts off, it should rev up a bit too.

Before you do all these, check and make sure the idle gap opening is set between .7-1mm (about the thickness of a credit card or drivers license).
Actually thats not what I was referring to, but thats another thing to do.

What I was referring to was the pinch of the cylinder. The sleeve has a taper towards the top to create compression since there isn't any rings. Get the motor hot and shut it off, then rotate the flywheel. You should feel a huge resistance towards TDC. If not, then it needs to be rebuild because it has no compression.

There are only a few things it could be causing problems. 2 strokes are very simplistic so it shouldn't be difficult to figure out. Only things it can be are the air filter, carb, glowplug, or the pinch (compression).

Air filter: Did you oil it? If so, you could have put to much oil, which can cause problems. Try it with no air filter and see if that helps.

Carb: this could be a number of things, but pretty much your only real possibilities are something like the LS or HS side could be clogged (highly unlikely), completely out of wack with the tune, or a cracked carb (again, highly unlikely if it hasn't been messed with). Another thing could be if it has a fuel filter, it could be clogged as well. Also check to see if there is air bubbles in the fuel line once you get it running (there shouldn't be).

Glowplug: Change the glowplug just in case. Its unlikely, but possible that its bad. It might allow it to idle, but then get put out when to much fuel is added. You can tell alot by the glowplug. It should be as clean as possible with a slight golden tint to it.

Pinch: As noted above, its very important to check the compression. If it has compression, don't worry about it and it shouldn't need rebuilding.

You need to do the basics first. New glowplug, new fuel line (keep in mind this is important since the one that goes to the pipe pressurizes the fuel tank so a crack in the line = no pressure, no pressure = no fuel), take the motor apart and clean it well (carb as well), clean the air filter and don't use to much oil, and make sure the nitro is still good.

Last edited by squeeforever; 02.15.2010 at 06:52 AM.
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E-Revonut
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02.15.2010, 10:22 AM

Def check the fuel line as squee mentioned, better yet replace it as it's cheap. My revo 3.3 was giving me all kinds of headaches, replaced the fuel line and ran like a champ again


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t-maxxracer32
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02.15.2010, 02:36 PM

sweet thanks for all the info guys! ill work on it later tonight and let you know how it goes.

its a nitro slayer BTW so its not terribly old.. the motor that is.
   
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02.15.2010, 04:38 PM

sounds like a glow plug to me. If you have access to a glow plug heater try revving it with the heater on, if it works then it's the glow plug.

never touch the low speed until the high speed is set. They work together and it is important to have the high speed set correctly first. If the high speed isn't right you'll just cause more trouble fiddling with the low speed.

if it's not the glow plug I suspect an air leak somewhere, or bad fuel. Fuel that sits min the tank will often have the alcohol evaporated out of it and it won't run worth a damn.


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t-maxxracer32
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02.19.2010, 04:01 PM

alright so heres the deal. I get the truck running fine and it idles good and everything like before. Now i got it set where i can drive around a little but once i go WOT or give it a little gas to go fast it dies out.

i cant remember how it went.. is it too rich and flooding it out?
or is it too lean and not getting enough gas?

the smoke is more greyish white and not exactly blue..

thanks
   
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wallot
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02.19.2010, 04:12 PM

just follow this flowchart and you will be ok

tuning-flowchart.pdf


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Bondonutz
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02.19.2010, 04:17 PM

Quote:
Originally Posted by t-maxxracer32 View Post
alright so heres the deal. I get the truck running fine and it idles good and everything like before. Now i got it set where i can drive around a little but once i go WOT or give it a little gas to go fast it dies out.

i cant remember how it went.. is it too rich and flooding it out?
or is it too lean and not getting enough gas?

the smoke is more greyish white and not exactly blue..

thanks
The smoke color doesn't mean much, with different brands the color may vary a little.
Unless it's old fuel ?

Sounds like it's starving on top, richin it up on the high side.


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