carb question
New User
Joined: Dec 2000
Posts: 19
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carb question
I'm having a problem when I step on the throttle to get up to speed I have to gently step on it, if I really get on it then it either dies or hesitates. Does the carb need adjusting or could it be something else. One more thing it is a 68 with a 1bbl Ford Carb
Senior User
Joined: Apr 2001
Posts: 243
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From: indiana
carb question
my truck did that when i let it run out of gas.
i refueled it and i guess all the gunk from the bottom of the tank got up in the system and i would have to give it gas constatly to keep it going. and if i gunned it it would hesitate and die if i kept on it. it runs fine again now. but i guess thats not solving your problem.
i refueled it and i guess all the gunk from the bottom of the tank got up in the system and i would have to give it gas constatly to keep it going. and if i gunned it it would hesitate and die if i kept on it. it runs fine again now. but i guess thats not solving your problem.
Elder User
Joined: Apr 2001
Posts: 772
Likes: 0
From: Glen Burnie Maryland
carb question
the accelerator pump is leaking.
When you push done on Gas pedal, the accelerator pump shoots an extra amount of gas into the throat of the carburator to compensate for the mixture change to lean. If the pump doesn't work correctly, then you get an overly lean mixture when you stomp on the gas pedal and the truck will hesitate or stumble.
Get a re-build kit. the kit will have all the necessary parts (gaskets, needle valve and hanger, accelerator pump, etc) you need to overhaul carb. Get a gallon can (with dip basket) of parts cleaner at auto store. remove choke housing and all rubber parts. dip the remaining parts in the cleaner OVERNIGHT!
Remove parts from basket and with an airhose or can of carb cleaner; clean all passages and parts. re-assemble with new parts.
Don't worry if you have two or three gaskets left over. Most carb kits will fit various applications and years.
Go by specifications for float bowl and idle mixture against your particular model # of carburetor. Different applications required different settings.
Larry
When you push done on Gas pedal, the accelerator pump shoots an extra amount of gas into the throat of the carburator to compensate for the mixture change to lean. If the pump doesn't work correctly, then you get an overly lean mixture when you stomp on the gas pedal and the truck will hesitate or stumble.
Get a re-build kit. the kit will have all the necessary parts (gaskets, needle valve and hanger, accelerator pump, etc) you need to overhaul carb. Get a gallon can (with dip basket) of parts cleaner at auto store. remove choke housing and all rubber parts. dip the remaining parts in the cleaner OVERNIGHT!
Remove parts from basket and with an airhose or can of carb cleaner; clean all passages and parts. re-assemble with new parts.
Don't worry if you have two or three gaskets left over. Most carb kits will fit various applications and years.
Go by specifications for float bowl and idle mixture against your particular model # of carburetor. Different applications required different settings.
Larry
Posting Guru
Joined: Mar 2001
Posts: 1,494
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carb question
Another suggestion (although I agree with the previous post) is to try leaning it out like you asked. You may be too rich and she's partially flooding when you hit the gas. If it is the accelerator pump your problem should be worse when you lean it out a bit.
Freshman User
Joined: Aug 2001
Posts: 26
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carb question
I'm having the same problem with my '86 300. The problem is significantly worse when the engine is cold. My initial thought went to acec. pump, so I popped off the air cleaner (engine off) looked down the throat of the carb and worked the throttle linkage by hand.
Now, my father was an old-school mechanic. Gave it up in the 80's when they started putting computers in cars, but still did work for friends with older cars. I remember spending Saturdays working on carbs with him, and when he did the same test I did, he was rewarded with a nice steady stream (or two, 2bbl?) of gas jetting down the throat of the carb.
I did not see this in mine. Does anyone know if this is a valid test on the 300's 1bbl carb? Should I have had the engine running to pressurize the fuel system, or would there be enough gas in the carb to jet out?
Now, my father was an old-school mechanic. Gave it up in the 80's when they started putting computers in cars, but still did work for friends with older cars. I remember spending Saturdays working on carbs with him, and when he did the same test I did, he was rewarded with a nice steady stream (or two, 2bbl?) of gas jetting down the throat of the carb.
I did not see this in mine. Does anyone know if this is a valid test on the 300's 1bbl carb? Should I have had the engine running to pressurize the fuel system, or would there be enough gas in the carb to jet out?
Elder User
Joined: Apr 2001
Posts: 772
Likes: 0
From: Glen Burnie Maryland
carb question
I'm having the same problem with my '86 300. The problem is significantly worse when the engine is cold. My initial thought went to acec. pump, so I popped off the air cleaner (engine off) looked down the throat of the carb and worked the throttle linkage by hand.
Now, my father was an old-school mechanic. Gave it up in the 80's when they started putting computers in cars, but still did work for friends with older cars. I remember spending Saturdays working on carbs with him, and when he did the same test I did, he was rewarded with a nice steady stream (or two, 2bbl?) of gas jetting down the throat of the carb.
I did not see this in mine. Does anyone know if this is a valid test on the 300's 1bbl carb? Should I have had the engine running to pressurize the fuel system, or would there be enough gas in the carb to jet out?
Now, my father was an old-school mechanic. Gave it up in the 80's when they started putting computers in cars, but still did work for friends with older cars. I remember spending Saturdays working on carbs with him, and when he did the same test I did, he was rewarded with a nice steady stream (or two, 2bbl?) of gas jetting down the throat of the carb.
I did not see this in mine. Does anyone know if this is a valid test on the 300's 1bbl carb? Should I have had the engine running to pressurize the fuel system, or would there be enough gas in the carb to jet out?
It's a valid test on all carbs. The accelerator pump works like one of those stand-up bicycle pumps (with a spring on the bottom to push up the shaft/seal assembly). There is a 1 way check ball at the bottom of the "pump housing" so when the shaft retracts, fuel can fill the housing. When you stomp on the gas, the fuel is now pushed out of the housing, thru the passages into the throat.
The only thing the fuel pump on a carb'ed vehicle does is keep the float bowl full. The fuel pressure is usually between 3-7 #'s (at least in my experience). The rest of the system is gravity feed or Vacuum powered....
There should be enough fuel in the bowl(if it's setup correctly) to pump 15-20 times before you run out of fuel (engine off).
Hope this helped.
Larry
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