LA 360 high idle

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d100clubcab

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Hi,

After 2 years or so ( Hydrolock??? ) I finally have been able to start my 360 up again
SHE RUNS!!!!
Moved her about 10 feet under her own power
Problem is, the idle is REALLY HIGH
too high!!!
You can see/hear what I'm talking about in that video clip

What could it be?
I've hooked up the brake booster so not a vacuum leak from there

Thoughts?
 
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bbrroowwnn said:
probably on high idle....let it warm up....then should kickoff high idle
Click to expand...
I have manual choke (I have to manually close the choke on the Eddy 1406 because there is no linkage hooked up)
Even with choke off it does this.
 
If it is warmed up, choke off (throttle blade vertically straight up and down), there is nothing else left to look at except making sure it is returning back against idle screw.....If it is on idle screw then you need to turn the screw counter clockwise until idle lowers to where you want it
 
You most likely have gunk in your idle circuit from sitting/crap fuel.
Remove needle and spring assemblies from top of carb. Remove idle screws from front of carb. Blow compressed air thru each opening of removed idle screw. Re-assemble and adjust idle screws (about 2 turns out each) is good staring point. Start up then re-adjust idle screws as needed. Turn one at a time until she starts to stumble then back out a half turn or so.
 
Just because the choke if off doesn't mean it isn't still on high idle on the cam of the choke linkage.
 
If you have verified that the choke is good. That there are no problems with the high idle. And that the curb idle is set properly. Then next I would:

Rebuild the carb. Break it down entirely. Soak everything in carb cleaner/acetone overnight. Being sure to remove any plastic parts of course. Blow carb cleaner through it (pressurized can type). Then blow compressed air through all the passages. Re-assemble. And follow AJ's guide to Transfer Port Synchronization to properly set it up for idle.
 
Oldschoolcuda said:
You most likely have gunk in your idle circuit from sitting/crap fuel.
Remove needle and spring assemblies from top of carb. Remove idle screws from front of carb. Blow compressed air thru each opening of removed idle screw. Re-assemble and adjust idle screws (about 2 turns out each) is good staring point. Start up then re-adjust idle screws as needed. Turn one at a time until she starts to stumble then back out a half turn or so.
Click to expand...

Lustle said:
If you have verified that the choke is good. That there are no problems with the high idle. And that the curb idle is set properly. Then next I would:

Rebuild the carb. Break it down entirely. Soak everything in carb cleaner/acetone overnight. Being sure to remove any plastic parts of course. Blow carb cleaner through it (pressurized can type). Then blow compressed air through all the passages. Re-assemble. And follow AJ's guide to Transfer Port Synchronization to properly set it up for idle.
Click to expand...


The carb was rebuilt but sat for over a year.
Only clean fuel has been through the carb as I'm running it off a 2 Gal can since I know the main tank is filled with old fuel/gunk.
This is wierd.
 
d100clubcab said:
The carb was rebuilt but sat for over a year.
Only clean fuel has been through the carb as I'm running it off a 2 Gal can since I know the main tank is filled with old fuel/gunk.
This is wierd.
Click to expand...

Sat dry? Or when you let it sit did it still have gas in it?

Gas these days goes bad in less than 6 months. Bought a car off a buddy to fix and flip, it only sat 7 months. First fire up it idled like garbage. Had to run injector cleaner and a fresh tank through it before idle cleaned up.

If it sat dry. I would still check it. Seals and such dry up, there could be something caught somewhere. Once again, this is assuming you've double checked choke/high idle for proper operation.
 
Lustle said:
Sat dry? Or when you let it sit did it still have gas in it?

Gas these days goes bad in less than 6 months. Bought a car off a buddy to fix and flip, it only sat 7 months. First fire up it idled like garbage. Had to run injector cleaner and a fresh tank through it before idle cleaned up.

If it sat dry. I would still check it. Seals and such dry up, there could be something caught somewhere. Once again, this is assuming you've double checked choke/high idle for proper operation.
Click to expand...

Picked it up from rebuilder
Sat dry in the same ziploc back he returned it to me in
Sat in the cab of the truck

Choke/High Idle operation are all the way off
High idle screw was almost taken out it's backed out so far
Truck will only start with choke engaged
no choke, no start
 
d100clubcab said:
Picked it up from rebuilder
Sat dry in the same ziploc back he returned it to me in
Sat in the cab of the truck

Choke/High Idle operation are all the way off
High idle screw was almost taken out it's backed out so far
Truck will only start with choke engaged
no choke, no start
Click to expand...

Any unused port caps missing?
Did you try plugging off a PCV hose if you have one?

I would have to lean towards the carb.
There are times with a dirty carb I have revved the engine holding the throttle open all the way open as I closed the choke almost killed it with the choke by hand.
Once in awhile it'll suck out the stuff causing blockages.

Just revving it and closing the throttle doesn't do the same thing, as all the vacuum is under the throttle plates only pulling on the idle and transition slots.
Revving and choking the crap out of it makes a big vacuum above the plates where the main fuel flow is.

Just something to try that works sometimes. :D
 
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The condensation alone created from sitting in a bag in your truck for a yr. or more would be more than enough to bogger up your internals.
My rule of thumb is if it sits for more than 6 months regardless of storage try my suggestion in post #6. Have had successs with that technique with multiple eddys that have sat. If that is a no go after trying rebuild it or replace it.
Eddies are simple carbs. to rebuild or relatively cheap to replace.
 
TrailBeast said:
There are times with a dirty carb I have revved the engine holding the throttle open all the way open as I closed the choke almost killed it with the choke by hand.
Click to expand...

This is what it needed.
I put on a heavy leather glove, started it up then put my hand over the top of the carb trying to choke it off as much as possible.
This settled it down to "normal" levels
Nice smooth idle.

But, still has really high idle. I mean soon as she fires up she is at 3,000-4,000 RPM


now I wonder if I have leaks around my intake/heads???
 
d100clubcab said:
This is what it needed.
I put on a heavy leather glove, started it up then put my hand over the top of the carb trying to choke it off as much as possible.
This settled it down to "normal" levels
Nice smooth idle.

But, still has really high idle. I mean soon as she fires up she is at 3,000-4,000 RPM


now I wonder if I have leaks around my intake/heads???
Click to expand...

Have you checked the primary and secondary throttle plates to see if they are open at all?
If they are not it almost has to be a vacuum leak.

The right base gasket (seals with no gaps around the base)?
The carb is down all the way and straight on the intake?
You have to keep in mind that the only way a normal engine can rev up is with extra air getting into the cylinders somehow.
Even like the float bowls section not being tightened down on the throttle plate section. (not applicable to Edelbrock 1406) but seen it on others.

Can you kill the engine with the choke only?
If not, or it's hard to kill with the choke you have a vacuum leak.
From your answer about the hand over the carb choke making it run better it should still come off for an inspection and cleaning.
 
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TrailBeast said:
Can you kill the engine with the choke only?
If not, or it's hard to kill with the choke you have a vacuum leak.
From your answer about the hand over the carb choke making it run better it should still come off for an inspection and cleaning.
Click to expand...

If I manually set the choke (there is no choke linkage I have to do it under hood myself) and start it up she runs at 4,000 RPM immediately on start up
If I loosen the choke screw and set the choke then starat it up, she'll be at 4,000RPM for 1-3 seconds before the vibrations from the engine shakes the choke off and then the engine dies (too much air???)

The engine won't run without the choke on
But with choke it's always above 3,000RPM (no tach, just guessing by sound)
 
I've had issues with Eddy carbs cracking in different places, maybe that's it?? Have you tried spraying carb clean around the carb and intake while running to see if it picks up the idle even more?
 



So, I had a feeling the intake had a air leak so I decided to reinstall it.
It actually helped things out a lot even though it idles a little higher than I'd like
But it still is not to where it was pre heads coming off
Still tinkering with it to get it to a nice smooth idle

And now it has to burn off all the oil/grease that was was spilled on the exhaust pipes
 
d100clubcab said:
So, I had a feeling the intake had a air leak so I decided to reinstall it.
It actually helped things out a lot even though it idles a little higher than I'd like
But it still is not to where it was pre heads coming off
Still tinkering with it to get it to a nice smooth idle

And now it has to burn off all the oil/grease that was was spilled on the exhaust pipes
Click to expand...


Got it to idle smoothly as it should (and did pre heads coming off)
Not nearly as much smoke coming off the exhaust pipes but valve covers still leaky
And now to add another headache I've sprunk a big water leak on the rear of the engine on the drivers side
I guess that water port didn't seal as well as the others
Sheesh!
 
Back up the bus a sec:
Did you say that you put your gloved hand over the carb air-horn until the revs came down far enough and then when you removed your gloved hand, that she idled at a normal speed?

If yes, I think there might be an easy fix in there.
 
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AJ/FormS said:
Back up the bus a sec:
Did you say that you put your gloved hand over the carb air-horn until the revs came down far enough and then when you removed your gloved hand, that she idled at a normal speed?

If yes, I think there might be an easy fix in there.
Click to expand...

Nope
Gloved hand on carb it brought down rpms.
Almost stalled/choked the engine and gradually released hand off carb then right back to high rpms.

High rpms isn't much of the problem now
I think that had to do with a bad seal on the intake so i reinstalled the intake
Got the rpms to come down to normal
Adjusted the fast idle screws and all to make it purr at idle
But now she is leaking in the driver's side rear water port. Uggghhh
So fix one thing another thing breaks

But what would have been your suggestion?
 
Well that is a classic sign of a confused carb., with a way-off T-port sync. The throttle blades are open just far enough that there is a strong enough signal to initiate a dribble through the boosters. The transfers are flowing and so are the idle ports. The mixture screws make almost no difference where you set them, cuz the percentage of fuel that they are now delivering is so small in relation to all the other fuel flowing through there.
Now when you eliminate the air flow thru the carb, the engine rpm drops to where it wants to stall, same as if you had shut off the key. But if just before it stalls, you again introduce the air, now at the reduced idle speed, the air flow thru the boosters has quit and along with that, so has the booster dribble. So the carb idles normally for a few seconds. Then because the throttle is still so far open, the rpm rises and the cycle begins anew.
The usual cure is to increase the idle-timing and shut down the curb-idle screw, restoring the T-port sync.
The kicker is if the intake is sucking air from elsewhere, unregulated by the butterflies. Then this situation does not arise. In fact;usually the opposite. The blades may be closed down waaay too far, to the point that the transfers are barely flowing enough.
And another is if the vacuum advance is hooked up directly to manifold vacuum, and there is enough signal-pull there to begin the advancement. As soon as the engine develops enough vacuum to activate it, the rpm rises, which increases the signal, which increases the advance and so it goes until all the vacuum advance is all in and then the idle speed stabilizes at a new higher,usually much-higher rpm.This can also,allbeit rarely, happen with the Vcan hooked to ported vacuum, a retarded idle timing, and much too-far open throttle plates; required to keep the poor thing running.
So once again, starting with a T-port sync, eliminates a lot of problems.

Now lets talk about the leaking water port.Is there any chance that you forgot to slot out the bolt holes in the intake, which would make it possible for it to slide down,or up, as the case may be, in compensation for any engine machining, such as decking,shaving,surfacing,or angle milling? And did you follow the intake torquing program? You know; the three-step circle pattern.
Happy fiddling,lol
 
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