EFI 300 converted to Carb swapped into my 78.

Before the blown motor I had a 268 comp cam and had a nice low idle. Now my.idle is really high. Choke or no choke. It grinds the tranny to get to first everytime. I have pulled the carb and reset everything to scratch and lowered the idle screw and its still idles high. Not rough. Pretty clean. Just high. I had a timing gun until it blew the bulb. So i don't know what timing is at. I get good clean acceleration. No lag. Even WOT just goes!

But any ideas? PS: Summit 600 Street Carb, 6:8 Clifford Intake. Stock Cam, Headers. Glass Packs

When I swapped engines should I have swapped the Sensors? My Coolant, oil and Gas max out everytime. My temp gauge on my radiator stays about 160. I Have oil (Had a leak creating smoke). Ideas? I can't find a short anywhere. The gauges all worked fine before the engine swap and the only wiring I touched was the sensors and Alt: JY 3g alt swap has been completed (Could this be it)

 

Have you completely disconnected the throttle linkage to rule it out? It's possible that your throttle cable is too short, or the cable itself is sticking. Disconnect it so you're just dealing with the carb.
After it's disconnected, back out the idle screw until you can see that it's physically no longer pushing on the carb body. Is it still idling high?
If so, can you push the throttle blades closed by hand and bring the RPMs down?

If not, you probably have a vacuum leak and are pulling in air from somewhere else.

As for the gauges, besides a short, I can't imagine what would make your gauges do that. But, not 100% sure what the best way to track that down is.

 

Throttle linkage is not it.

Have backed out the screw. Never thought to try touching the plates. I will grab a screw driver later and see what happens. Cool idea.

I just replaced all the tubes a few months ago. Guess I will get a new carb gasket kit I have a feeling that might be it. The carb is just laying on the mount bracket without a gasket.


I find it wierd that all 3 did it. Hmm

 

So bumping stuff around I think I found a culprit.

I first put new studs on and the Summit Gasket that was included. Idle calmed a bit.

I used a screwdriver and couldnt get a result inside the insides. However I moved the red lever between the choke and the carb and the idel dropped. And I could finally adjust idle with the screw. Any ideas?

 

Good to hear. If that helped your idle smooth out, it sounds like you had a vacuum leak.

I'm not sure what your asking here. Any ideas on what?

And maybe it was an autocorrect on your phone, but what do you mean you "couldn't get a result inside the insides"?

What is the red lever?

 

I've had a couple of the Summit carbs. One would jump back a notch on the fast idle cam on the choke when I was driving down the street. Iirc, there's a little plastic arm on the clutch mechanism with 'stairs' on it. When you find that, loosen you choke setting when the engine is to running temp, and try to rev it by hand, just a bit. With your other hand, move that little stair fast idle gizmo to it lowest step, and then release the throttle. Did that help? Heck, just leaning out/loosening the choke might do it. But check.

 

Yes its the fast idle screwing with it. How do I loosen it so it quits hanging.

 

Ck the short ground wire from the electric choke and make sure it is not loose. To set the choke, you need to go out to the vehicle early morning when it is coldest part of day and the engine is cold. Pull the air cleaner. Pump accelerator/throttle once. The choke plate/flap should flip closed on top of the carb, primary side. Loosen the three screws on the black dial to allow you to turn the dial. Turn dial until the flap is like 1/8 of an inch still open, then tighten the screws.

Ck also youtube. Iirc, there was a vid by a guy who is dialing in a Summit carb, which is a Holley redesign of the old Autolite 4100. He shows how to set up the entire choke. That might help. Also, summit has heaps of helpful vids on their youtube channel. Good luck.

 

Yeah its all setup correctly. Just the fast idle gets caught

 

At the risk of not sounding like a nice guy, I'd say that if everything were setup correctly it wouldn't be hanging on the fast idle step. Did you ck that youtube vid I mentioned? Good luck.

I used to fly frequently in a private plane with a pilot who had thousands of hours experience. Before each flight he'd take out a ck list and physically walk around and ck each item on the list. Why? Because just going 'oh, yeah, that's good' with a plane can get you killed. Why do I mention this? Because as with flying, mechanical work often requires the same physical checking to find a problem. Good luck.