3 Needle
 

Hey everyone, I have a Savage 25 with the 21 3 needle carb. I can't get the truck to idle and I was wondering if anyone knew where I could begin to tune it. I already tried the factory settings but they are for the 21 so it doesn't work. Also, I know its not the glow plug and anything else. Thanks for any help.

RE: 3 Needle
 

You need to give a little more info first

What happens when it dies?
How old is the engine?
What fuel Nitro% are you running?
What Glow plug are you using?
Does it still have good compression?

If it has good compression it should idle
If you running 20% nitro or lower you'll want to run a medium to hot glow plug
if you're running 30% you'll want to run a cold plug
If you're runnign the wrong plug ( a cold plug with low nitro) it will not want to tune well

Assuming you're running the right plug and the engine still has compression, try this
At the Factory needle settings
Fire it up and get it up close to full temperature Keep the RPMs up and try and set the HSN to a point where the engine comes up to full speed, and clears out going down the straight.

then let it come to idle,,,What happens when it dies?
If it seams to start gurgling then dies try leaning the LSN 1/12th a turn at a time
If it seams to stay at a high RPM and then surge (ping ping ping) and die, try riching up the LSN

RE: 3 Needle
 

What do you mean what happens when the engine dies? It just like stops no high revs and then stops it just stops. The engine has little over a gallon through it. I'm using 20% nitro, blue thunder. I'm using o.s. 8 glow plugs and the engine has great compression. Well the factory settings won't work because the engine it was factory set for was the .21 and I'm running it on the .25. I'll try the high speed thing you recommended but it doesn't do either of gurgling or pings before it reaches idle. It just stops. Thanks any advice.

RE: 3 Needle
 

Have you adjusted the Idle stop screw?
make sure it holds the barrel open .5mm-1mm
20% with a #8 plug should be fine

Are you sure the clutch isn't binding up,,,that's a reason for engines stoping at idle too

Go ahead and use the factory settings for the .21,,that will be close enough
they are always on the rich side anyway, so don't be afraid to lean the low speed neddle a little at a time until it will hold an idle, just keep an eye on the temp,,don't let it get to hot

RE: 3 Needle
 

I know its not the clutch, the wheels spin like crazy when it starts. I have gotten it to kind of idle but it won't stay alive for long and I have to hold half throttle for it to idle. I'll try the stock .21 settings again and atempt to fix it.

RE: 3 Needle
 

If the wheels spin like crazy when it starts, it means your clutch is engaged. In other words your clutch is binding. Your wheels should not spin when in idle. Fix you clutch.

RE: 3 Needle
 

Unless you're a hardcore nationally competitive racer, a 3 needle carb won't do you any good. Most people never even touch the MSN

RE: 3 Needle
 

The clutch is not binding, when the truck does idle the wheels do not move. When I start it the engine revs really high so the clutch engages. The thing is that I can't get the engine to idle consistently and to stay alive. I can get it to idle for a little while if I hold the throttle to about half way, does this mean that I have to adjust the idle/low speed/high speed needle a certain way? Thanks.

RE: 3 Needle
 

Which ones are which?
A)?
B)?
C)?
D)?

RE: 3 Needle
 

A) HSN aka High speed neddle
B) LSN aka Low speed needle

C) Throttle stop screw , this sets the air gap so the it doesn't get completely cut off when you apply brakes, it should be set .5mm minimum to 1mm max open while holding full brakes,(they say 2mm,but that sounds like alot to me) take the air filter off and get it adjusted before you do anything else, Do not adjust it while holding the brake on!! you can damage the screw and or the barrel

D) Leave it alone,, should be set flush,,Some people call it the midrange needle but it's really just sets the splash bar position,,leave it flush with the brass case,, If you move it you'll have to move the LSN also

Good luck

RE: 3 Needle
 

When I adjust the idle speed screw it seems to being doing nothing to adjust the carb opening. It always returns to the same spot and when I tighten the screw some more it gets really tight and the carb cannot move anymore so I have to loosen it again.

RE: 3 Needle
 

Didn't you see this above

Do not adjust it while holding the brake on!! you can damage the screw and or the barrel

You need to hold he throttle open a little as you make you adjustments

RE: 3 Needle
 

I was holding it open while I made the adjustments. Also I was trying to tune on Sunday and I did get it to idle a little but that was when I had the throttle a little open, just a little over closed (when it should idle). When I would close it the engine would die. I have the right size for the carb opening but it still shuts off, what do I need to change?

RE: 3 Needle
 

I think B is your Mid Range Set screw and D is the Low End Setting.

BTW, is your fuel filter clean? And did you change your plug to check it?

RE: 3 Needle
 

Sorry, Bud you're wrong

Another example of a typical 3 needle carb
http://www.ofna.com/pdf/eng-hyper21.pdf

RE: 3 Needle
 

I stand corrected. Don't read when your sick. Last night I was reading the article from RC Car Action April 2004 Piston Power Fact & Fiction 3-Needle Carbs. It shows details of the carb.

Now I was looking thru an LST Manual online and saw in the carb section that I was wrong in the carb needles. I went back to re-read the article and I stand corrected. So I am retracting my earlier posting. Sorry if I confused you.

RE: 3 Needle
 

No worries,,,Everyone makes mistakes

Hey???
Lt. DEATH
Did you get it working yet?

RE: 3 Needle
 

Well I finally got it to run yesterday. All that time! BTW I found this site very useful in helping me tune it

http://home.att.net/~dgelowitz/savage_faq/#P-24

RE: 3 Needle
 

heres a problem, just incase ne one does the same.

"Also I was trying to tune on Sunday and I did get it to idle a little but that was when I had the throttle a little open, just a little over closed (when it should idle). When I would close it the engine would die"

if u close the barrel all the way, it will die. as a rough guide, have the barrel about 2 mm open (assuming the tuning is allmost perfect) then close it until the wheels stop moving, but the engine is running. unless u have an old marauder where a bolt went thru the bottom of the carb, thru the engine to hold it on. when the seals went, it leaked air so i would close the barrel and it would lean out and fly off.