Idle mixture?
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From: carova beach(OBX)
Idle mixture?
My 1980 f-250 351m is not running good at all. It ran good untill one day it just started missing. It almost seems like the timing is off but the distribulor is tight and was just tuned in last month. I was thinking mable the mixture srews are out of adjustment. Its a holley 4bl. carb. Any suggestions? It also has been getting worse. It doesn't want to stay running.
Cargo Master
Joined: May 2003
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From: Earth
If it has a miss and it started after you just got the tune-up, I would check for a loose spark plug wire, both on the distributor cap and the boots on the plugs. I would check those first. If that checks out ok, I would then start looking for vacuum leaks.
Last edited by 53fatfndr; Apr 11, 2006 at 04:06 PM.
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From: carova beach(OBX)
Put new plugs and wires on anyway. No difference. Then started playing with mixture screws. The cork seals around scews were shot. Runs better than ever now. (I also rebuilt the carb)
Only problem is it pulls the most vaccum with scews all the way in. I don't know if that is normal, i would think not. it also doesn't want to shift on its own. What do you think would cause this? to run third gear i have to get cruzing down the road and shift to neutral then down to "D"(no overdrive trans). Used to shift fine before the carb problem. What do you think??
Only problem is it pulls the most vaccum with scews all the way in. I don't know if that is normal, i would think not. it also doesn't want to shift on its own. What do you think would cause this? to run third gear i have to get cruzing down the road and shift to neutral then down to "D"(no overdrive trans). Used to shift fine before the carb problem. What do you think??
Cargo Master
Joined: May 2003
Posts: 2,561
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From: Earth
Originally Posted by carova_kevin
Put new plugs and wires on anyway. No difference. Then started playing with mixture screws. The cork seals around scews were shot. Runs better than ever now. (I also rebuilt the carb)
Only problem is it pulls the most vaccum with scews all the way in. I don't know if that is normal, i would think not. it also doesn't want to shift on its own. What do you think would cause this? to run third gear i have to get cruzing down the road and shift to neutral then down to "D"(no overdrive trans). Used to shift fine before the carb problem. What do you think??
Only problem is it pulls the most vaccum with scews all the way in. I don't know if that is normal, i would think not. it also doesn't want to shift on its own. What do you think would cause this? to run third gear i have to get cruzing down the road and shift to neutral then down to "D"(no overdrive trans). Used to shift fine before the carb problem. What do you think??
Also, if the line is connected, check for cracks in the line, specifically the hoses on both ends. The vacuum line should be a solid steel line with a couple inches of rubber line on each end. These do crack on occasion and will cause the same problem as if the whole line has come off. Keep us posted
Last edited by 53fatfndr; Apr 12, 2006 at 07:42 PM.
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