Scout 80 no curb idle

T

Todd Jo

New member
Hi all. I have a 64 s80 with a 345/tf727 transplant. I have just brought it out of the garage and it will not run correctly. I cannot get the thing to idle in park under 1100 rpm without surging and eventually it dies. If I put it in gear it does too. Tried spraying for vac leaks, none found. New plugs, dwell at 27*. I rebuilt the Holley 4150 which has been on it for years. No improvement after rebuild. I am wondering if I somehow developed a crack in the intake? If so does it need to come off to find it? What else can I do before I roll it off a cliff?
 
I doubt that you have crack in the intake. Your dwell angle is a little off...28-32 degrees is ideal for a v8, but that wouldn't be causing your issue. Has the timing been adjusted? Spark plugs/wires changed? How long has it sat dormant? When did it last run properly? Have you tried fiddling with the idle speed screw as well as the a/f mixture screws on either side of the metering block? Have you verified that the throttle linkage moves freely and is not bound up or sticking? Does it have auto or manual choke and is the choke mechanism functioning properly?
 
I changed the plugs today. It has sat for about 1 1/2 years. It ran perfectly before. Manual choke. Choke and throttle linkage disconnected. I have nearly wore out my remote starter. Even drained the tanks and using fresh fuel and new fuel filters. I have played with idle speed screw as I said it won't stay lit under 1100 rpm. At that engine speed mixture screws don't seem to have much if any effect. I tried a edelbrock carb that I had lying around and had similar but worse luck with it. I am starting to think I have a vac leak or leak at the intake. I just don't get any feedback when I spray carb choke cleaner all around the manifold and vac lines. Tried while having all ported a d manifold vac ports capped/plugged as well. Engine speed raises considerably when sprayed into the carb.
 
In your initial post you described the carb as 'surging and eventually dies' - I think that is how you put it. Is that still true? Below 1100rpm the motor rpm raises and falls, if left to itself it'll idle slower and slower and shut offf? Is that a fair description?
If 'yes' then that is the classic sign of vacuum leak where the engine gets air but no fuel to burn.
A few spots to look for leakage would be powerbrake booster seal; vacuum pot seal at the distributor, either of these would escape the carb cleaner spray test and would exist while changing carbs.
Is the engine healthy?
 
I replaced the carb to intake gaskets. Checked to see if the gaskets in the carb were not shifted or incorrect. I have the ported vac to the dizzy capped. I do not know how healthy the engine is. It was a acquisition that led to me putting it on. The old it ran when pulled it deal. I have used this rig on and off for about 8 years with no real problems. After replace carb to manifold gaskets the surging described has gone away. I can now get it to idle down to 850 rpm and it sounds good, smooth. But only with careful manipulation of choke. The choke blade needs about 3/16-1/4" gap to run at all. No choke won't run. All choke won't run. Also wont run with out pumping the gas to restart every time it dies. This sort of thing was easily remedied over a chili dog and bs session. I sure miss mayben!! Hope your okay!!
 
That much finick with the choke setting leads me to believe that something went amiss with the carb rebuild and/or you May have a gasket port miss-match inside the carb. Did you use a Holley kit? Even so, the Holley kits that work with the 41xx series mixers take a "one-size fits all" approach when in fact one size does not fit all with 100% precision, especially when it comes to the list numbers that pertain to ihc applications. When you did the rebuild, could you tell if the gaskets you removed were original? Do you still have them? To solve this, there's a good chance that you May need to bust the carb down again, take and post clear pics of your carb parts that have gaskets between them, and also pics of the gaskets themselves. It just May be that your new gaskets are lacking a hole or holes where one or more should be. That's kind of the unwritten and all too often unspoken hurdle that one faces when rebuilding carbs that don't have rebuild kits specific to their list model available for purchase. Sometimes you have to make minor alterations to make it work properly.
 
I did fwiw call Holley because I ran into what you are describing before. He was able to give me the original application by list number so I had better have the right kit. Well for now the heat is off so to speak. I will take pics as described and try to post. Unfortunately for now the Scout is buried and no longer next in line
 
Do you have an active pcv system on the 345? They usually do..
The second thing I would ask for is a couple of clear photos of the vac/fuel plumbing. Get everything.
Right now you've asked us to shoot in the dark.
 
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