87MagnumII

I had a thread earlier about my engine not idling down and I got it slowed down but now it struggles to stay running and is hard to start. I'm thinking the mixture screws are out of whack and could use some help on what does what. I'll give a brief synopsis of the setup as accurately as I can.

350 CID
LT4 hot cam
650 demon carb
V6-14 module with around 31-32 total timing at WOT

I unhooked my throttle cable to eliminate any cable misadjustment when trying to tune the carb
I set the 4 corner idle screws to 2 1/2 turns out
I set the Idle Eze screw to 1 1/2 turns out per the manual (this screw is under the aircleaner stud)
The idle adjustment screw on the throttle arm is not applying any tension or pressure to the throttle arm
Engine is idling around 650-700 but is struggling to stay running and is almost impossible to restart. A few shots of fuel make it worse so I'm thinking that I may have the mixture to rich. Before I made the changes it was very easy to start but idled to high and was a smooth idle. Now the idle is lower but very erratic and lazy.

Should I turn the screws in some more and lean the idle out some? It's acting almost like the choke is on but I can snap the throttle by hand it takes right off without a stumble.

Trash

I am going to come right out and say I don't know diddly about carbs. I'm an EFI cripple. If I was you, I would install a wide band and that would take the guess work out of what was going on.

Have you tweaked the timing at all around idle? That may help too. Just a thought.

phughes69

Here are a couple of tips I learned from trying to adjust my idle on my engine recently.
1. check your tach against another tach- I found out my factory tach was reading 300 rpms high so when I tried to idle it down to 800 it was actually trying to run at 500 and mine hated that.
2. hook a vacuum gauge up to the intake manifold and tune it that way.
3. lean it out until the rpms stop going up. then adjust the idle screw to get your idle back down.
I believe that the EZ idle screw lets in extra air without adding more fuel. You could close the Ez idle screw and open the idle adjustment screw. You can tell when the throttle plates are opening by listening to the whistle as more air goes past them.
4. As a reference my engines (draw thru twin turbo BBC) like to idle at 12.3 AFR. I try to adjust it with the AFR meters but had better luck with a vacuum gauge and an accurate tach.

ezstriper

locking the dist and setting timing @ 34-36 will help idle, ck timing at idle see if it falls off while idling, a wideband 02 should be used to get carb dialed in

87MagnumII

I finally got it dialed in. I had the corner idle screws way to rich and it was loading up. Thanks for all of the help though.