Idle?

[Al rumble]

So I was trying to tune my 351c 2v with edelbrock carb this afternoon. It was pinging a lot after a long winter. She has fresh 93 octane fuel.

I set the idle mixture with the rpms at 300 then set the advance to 10 degrees. Then I set the idle with it in gear and lights on at 675rpm.

I took her for a burn and it ran better than ever.

Then I took it up some steep hills and gave her some juice. After that, the idle dropped down to about 300 and it sounded like crap. I checked the advance and it hadn't chaged? So I turned in the idle screw and brought it up to about 500, still didn't sound great. Turned it off then back on and idle went through the roof?

Does this sound like the idle circuit in the carb needs to be cleaned. I have never had it apart but I'm sure some eight year old on you tube can show me how.

Any advice would be great

 

[Mikes73]

The quick and easy way is to remove the idle mixture screws and blow compressed air or carb cleaner in where the mixture screw were. Sometimes that is all it takes, if not a tear down and thorough cleaning may be in order.

 

[Justin71]

I don't know anything about that carb, but what is going on with your choke? Is it electric, does it have power? Could the choke be malfunctioning? if it's working car will run great, but then if you get on the throttle up/down, maybe you are sticking on fast throttle when you shouldn't I don't know. Particularly, if you shut it off, and then back on, could choke be taking your idle back up high even tho engine is warm?

I'm not much of an engine tune man, but 300 sounds like a pretty slow idle to me.

Just some random thoughts.

Jay

 

[Al rumble]

I think the electric choke is fine. But I will double check after some carb cleaner and air.

 

[barnett468]

.

disconnect the distributor vacuum advance until the prob is fixed . . yes it does sound like a plugged idle circuit . . if it is, the screw on the plugged circuit will have little to no affect when you turn it.

make sure the points are clean and set them and clean the inside of the distributor cap.

 

[Mikes73]

Might as well blow out the idle bleeds (small brass tubes left and right on top of carb) while your at it.

 

[JimNiki]

Give the mech weights inside the dizzy a little spray also in case they are sticking/jamming sometimes.

Obviously, you've checked with the timing light that they are advancing the timing as per normal?

 

[Al rumble]

Looks like air and carb cleaner did it.

A good cruise this weekend will be the test.

Thanks all

 

[72HCODE]

this actually sounds like your idle air bleeds are set too lean.

if you do find having issues again after your test drive then open the bleeds 1/4-1/2 turn and retest.

hope you did get it good luck.

 

[Mikes73]

My edelbrock likes 1 1/2 turns out exactly on the idle mixture screws, no more no less and I have had alot of time tuning it. On my 351c 2v I have orange step up springs, 98/92 primary and secondary jets and 70/42 metering rods. For timing mine runs best with 12* base timing and 26* mechanical for 38* total timing all in at 2500 rpm using a duraspark distributor with accel advance springs. This thing will get up and go pretty good for a 2v. As mentioned buy 72hcode make sure the idle mixture screws are set right, to lean it will run hot at idle and putting around.

 

[MotoArts]

Did you first check for vacuum leaks? Bad hoses, etc.

Just had to replace one on my 5.0 that wouldn't idle.

I wouldn't turn a screw on a previously good carb setting until I eliminated all other possibilities.