carb trouble
01-26-2008, 11:14 PM
#1
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carb trouble
i have a 72 newport 400 2bbl and it surges alot and hesitates and sputters, my idea is to find an older simpler 383 2bbl that will hopefully work better than this silly carb is this the best idea?
also i have a 72 sportsman van 318 2bbl and it hesisates from takeoffs i have to feather the gas to keep it from dying, the guy i bought the van from said it was a newly purchased carb that was a rebuild, by the way it looks i beleive him. again would it be better to get an older carb?
in both situations losing power isnt really too much of an issue to me i dont drive hard anyway otherwise i would just put 4bbls on both of them
also i have a 72 sportsman van 318 2bbl and it hesisates from takeoffs i have to feather the gas to keep it from dying, the guy i bought the van from said it was a newly purchased carb that was a rebuild, by the way it looks i beleive him. again would it be better to get an older carb?
in both situations losing power isnt really too much of an issue to me i dont drive hard anyway otherwise i would just put 4bbls on both of them
01-27-2008, 07:34 AM
#2
First, I don't know where you are located, and how cold the climate is, so that may have a bearing.
Next, 72 was "starting" to be the "pain in the a##" years of smog control. Chrysler, instead of using smog pumps, like GM and Ford, played around with things like cam timing, ignition retart, and leaning out the carb to meet smog requirements. By about '76 they had leaned things out so much, that some of these cars were very poor to drive on cold startup--'specially in winter.
Further, you need to try and "figure" whether you actually have something wrong with the carb--IE dirt or corrosion, and these carbs are getting OLD--or whether this is typical from "smog" settins, or whether maybe you have ANOTHER problem, which can be---
The choke may not be operating properly, or set wrong
The idle screws may be set improperly, or the idle passages partially plugged
The accellerator pump may not be working correctly--the pump "leather" may be worn and stiff, or again, corroded or dirty pump discharge passages
Generally, the cruise and power circuits may be suffering the same fate
It's been a long time since I've followed the replacement carb situation. I would NOT go out and buy a factory "rebuilt" carb. I would investigate either
cleaning out (with chemicals) your present carb
investigate an aftermarket "street" carb
I would NOT put a "street/strip" or "race" carb--you mentioned 4 bbl--such as a "double pumper. These sound like driven cars, and you'd get horrid mileage.
The problem with putting 4 bbls one these, is that you'll have to change the manifolds, forget adapters, and you'll have the same problem. What to do for a carb? You haven't solved anything.
If you are not faced with yearly smog certification in your area, I'd look for a clean '71 or even '70 down to about '68 carb, clean them up, and use them. I realize that FINDING such a thing might be tough.
If it were me, I'd check with Edelbrock/ Holley/ Carter for replacement carbs.
Next, 72 was "starting" to be the "pain in the a##" years of smog control. Chrysler, instead of using smog pumps, like GM and Ford, played around with things like cam timing, ignition retart, and leaning out the carb to meet smog requirements. By about '76 they had leaned things out so much, that some of these cars were very poor to drive on cold startup--'specially in winter.
Further, you need to try and "figure" whether you actually have something wrong with the carb--IE dirt or corrosion, and these carbs are getting OLD--or whether this is typical from "smog" settins, or whether maybe you have ANOTHER problem, which can be---
The choke may not be operating properly, or set wrong
The idle screws may be set improperly, or the idle passages partially plugged
The accellerator pump may not be working correctly--the pump "leather" may be worn and stiff, or again, corroded or dirty pump discharge passages
Generally, the cruise and power circuits may be suffering the same fate
It's been a long time since I've followed the replacement carb situation. I would NOT go out and buy a factory "rebuilt" carb. I would investigate either
cleaning out (with chemicals) your present carb
investigate an aftermarket "street" carb
I would NOT put a "street/strip" or "race" carb--you mentioned 4 bbl--such as a "double pumper. These sound like driven cars, and you'd get horrid mileage.
The problem with putting 4 bbls one these, is that you'll have to change the manifolds, forget adapters, and you'll have the same problem. What to do for a carb? You haven't solved anything.
If you are not faced with yearly smog certification in your area, I'd look for a clean '71 or even '70 down to about '68 carb, clean them up, and use them. I realize that FINDING such a thing might be tough.
If it were me, I'd check with Edelbrock/ Holley/ Carter for replacement carbs.
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