Topic: Why would the engine while accelerating bog down??


ramin    -- 02-24-2010 @ 3:59 PM
  I have a 1938 FORD pickup. Recently the engine bogs in 1st and 2nd gear. I have taken out my HOLLEY 94 CARBURETOR 91-99 and cleaned the jets and everything else that i could taken out. I have been using ARCO gas for long time, and i am sure somewhere it is clogged up!! I even took out the fuel pump and cleaned it. I am debating if i should buy a reconditioned carburetor. Again i am not sure if that will resolves the issue.
Thanks,
R


trjford8    -- 02-24-2010 @ 7:55 PM
  How clean is your gas tank? You may have some dirt/rust that is partially clogging the pickup tube.


ford38v8    -- 02-24-2010 @ 9:39 PM
  R, I agree with Tom, but will put it another way: When your engine requires more fuel than your fuel delivery system can keep up with, your carburetor bowl goes dry off & on. This may be the bogging down you describe.

At fault may be the fuel tank, fuel line, the flex hose on the firewall, the fuel pump, or the carburetor float level. I would start with the assumption that you are getting debris in the fuel pickup tube as Tom suggested. Remove the flex line and blow back into the tank, to see if you have a temporary improvement when you hook it up again.

Alan


Pauls39    -- 02-25-2010 @ 7:51 AM
  If the car bogs from the start then picks up the problem is likely with the accelerator pump. If it just lays down all the way through the gear look to the power valve. The accelerator pump stroke can be changed by moving the link to a different hole in the cam at the base of the carb. With the engine off look down the top of the carb while you open the throttle. You should see two good squirts of fuel.
Have you replaced the power valve with one from a carb kit? As I recall they should open at 6.5 inches of vacuum. Replacement parts are often poorly made or incorrect for the application.
If the vacuum ports below the throttle plates are blocked or the power valve is not correct or fitted properly, the power enrichment system will not work.
Also check your float level to besure there is enough fuel for the systems to work.


supereal    -- 02-25-2010 @ 11:01 AM
  Did the problem exist before you cleaned the carb? Almost always, a change in operation is due to the last thing you did. The power valve is designed to provide more gas when the vacuum drops, as when the throttle is opened during acceleration or on a hard pull. We often find that the carb kits provide a gasket for the valve that covers the vacuum port for the valve, preventing it from opening. You should also check both fuel pressure and quantity at the carb to be sure the problem is not starvation of fuel. Also, a vacuum leak anywhere on the intake manifold will produce those symptoms. I'm attaching a vacuum gauge chart to assist you in solving the problem.


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