Idle/LSN question...

[JAD.]

Hey guys!

Just a quick question, I'm running a Mach 427 in my LST2 with 15%.

I've gone through the break in and have been getting her up to speed, the problem is sometimes i feel as if i have reached a good setting but when i stop the truck will idle normally for 5 or so seconds after which the revs will shoot up dramatically and spin the wheels until i blip the throttle.

Does this mean my LSN is too rich or lean? or is this an idle setting problem? or have i got it completely wrong and its a HSN issue?

Any help would be much appreciated.

Cheers! Jad.

 

[greenwing7]

either the idle gap is set too wide open on the carb or you need to ritchen the low speed needle, more fuel should help bring the RPM's down, remember to only adjust the LSN when the engine is up to temp

 

[JAD.]

Yeah i think you are right, the problem is that i have the LSN too high to compensate for the high idle speed. Ill give it a go and tell you how it went.

So how should the idle behave if you have it set right? Should it idle normally for 10 - 20 secs then go down in rpms? or should it just cut out?

 

[greenwing7]

well you should be able to idle for quite awhile if everything is ok at least 15 seconds, a lot of people us the pinch test, do a search on it I think you pinch the fuel line and depending on how long it runs here < or > 4-5 seconds you will be lean or rich respectively.