Idle Adjustment Screw!?

MarkieMark231 · #1 06-24-2006, 10:43 PM

I'm having some problems with my idle. I think I have the tune down correct but when I start it up sometimes it gets going and I have to tap the brakes to get it to idle normally again and other times it seems to run ok. I know where the idle screw is should I try adjust my idle and if so which way does what? I don't know if this has anything to do with it but also when I slam my brakes for 2-3sec it shuts down I'm not sure what to. Any suggestions thnx

rocknbil · #2 06-24-2006, 11:15 PM

Most likely the TX trims are "holding" the throttle open slightly. When you tap the brakes, something in the linkage is hanging up and holding it at a normal idle.

If it dies when you hit the brakes, one of two things are happening: either the idle screw is set too far closed and it's closing off the air flow, or it's tuned with it idled too high and the clutch shoes are dragging on the clutchbell. When you hit the brakes, this drag is stalling the engine.

First, the idle speed screw is nothing more than a bolt that stops the carb from completely closing. Turn it in to increase idle speed, turn it out to decrease idle speed (opposite of your tuning needles.)

The way to set this up is to set the TX throttle trim less than halfway to brake. Not all the way to brake, because anything on the "brake side" is going to allow you to adjust more brake as you are driving with the trim, without screwing up the idle.

Now with all the electronics on, remove the air filter and work the throttle from IDLE to BRAKE. The barrel/slide should not move at all. If it does, your TX is holding it open. At this point, adjust the linkage so at your resting position on the TX, the carb is resting fully against the idle stop screw.

Now no matter what you do on the TX, the carb cannot close far enough to stall. Put the air filter back on, start the engine, and adjust the idle screw so the engine will run as slow as possible at idle and full brake without stalling. If you are idling and hit the brake, there should be no change in the engine RPM. (The only exception is in an AE GT stock clutch, because it doesn't have springs in the clutch and the clutch is always semi-engaged.)

balang_479 · #3 06-25-2006, 11:25 AM

I COULD NOT ONLY BE THAT TX ADJUST IS WRONG..

It could stil be at idle on the servo but i would accelerate.. the revs build up and turn the wheels, then you tap the barke which stops the clutchbell turning which puts friction on the engine and slows it down..

Its not problem, when the you put the car down the car should not move fowards and thats the most inportant thing.. you could always add a bit of braking to the servo.

You may also need a stiffer clutch for the cutting out problem.. but you may also want to try and lift the idle...

rocknbil · #4 06-25-2006, 01:18 PM

Quote:

you could always add a bit of braking to the servo

balang if you do this and the idle is too high, either from a TX adjustment or the idle screw, this is a sure recipe for a burnt out clutch.

JoeMAXX · #5 06-25-2006, 11:18 PM

Quote:

Originally Posted by MarkieMark231

I'm having some problems with my idle. I think I have the tune down correct but when I start it up sometimes it gets going and I have to tap the brakes to get it to idle normally again and other times it seems to run ok. I know where the idle screw is should I try adjust my idle and if so which way does what? I don't know if this has anything to do with it but also when I slam my brakes for 2-3sec it shuts down I'm not sure what to. Any suggestions thnx

Erratic idle can be a few things A burnt clutch sticking clutch will do What Rockinbil says and the engine will stick at idle. If this is not the case I will take this one step further then Rockinbil.

The idle screw should be adjusted as he says with an opening of the size of a credit card/drivers license when viewing it with the air filter off and the electronics off.

The next step is to adjust your LSN with the engine at normal operating temps. Pinch the fuel line when at idle and it should run for 3 to 5 seconds. If it does not run for this long then adjust the LSN counter clockwise 1/8 of a turn and retest until it does. Always run a minute or 2 before re-testing.

If the Idle is still erratic then you may have an air leak at the Carb Base and this requires a little more knowledge to fix. You will have to pull and clean the engine then seal the carb. This is done by snugging the carb without putting too much pressure or using a sealant.

If this it case come back and ask Again then I will give you specific instructions on how to perform this.

rocknbil · #6 06-26-2006, 09:55 PM

Quote:

Originally Posted by JoeMAXX

...The idle screw should be adjusted as he says with an opening of the size of a credit card/drivers license when viewing it with the air filter off and the electronics off.....

Hold the phone!

If the TX trim is holding it open, when you turn on the electronics it will open it beyond the point of the idle screw, and you're back to high idle. I would set this with electronics ON (and engine off.)

JoeMAXX · #7 06-26-2006, 11:37 PM

Quote:

Originally Posted by rocknbil

Hold the phone!

If the TX trim is holding it open, when you turn on the electronics it will open it beyond the point of the idle screw, and you're back to high idle. I would set this with electronics ON (and engine off.)

Yea well could be a typo on my part or I am just brain dead