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Old 03-04-2021, 08:19 PM   #32
scicala
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Join Date: Jun 2010
Location: Detroit suburb, MI
Posts: 3,697
Default Re: carb leaking gas, what did I do wrong?

Quote:
Originally Posted by moefuzz View Post
.Your fuel pump is mechanical or electric?

The original mechanical fuel pump on top of your intake may be pushing to much pressure.

Your carb is not designed to handle over pressure for very long and can be over
powered by the fuel pump in a matter of seconds, minutes or hours...
...until it can't physically hold back the excess pressure anymore and it will finally give up.


Quick and easy fix=


You can add an extra gasket (or 2) underneath the fuel pump stand at the intake,

this has the effect of shortening the fuel pump pushrod and will decrease fuel pump pressure somewhat.

The longer the fuel pump pushrod "appears" in relation to the physical height to were it is mounted dictates fuel pressure.


So Hypothetically, if you (don't do it!) were to grind the fuel pump push rod a 1/16th or an 1/8th inch, it would have a shorter stroke and would not push the pump as far or as hard.

Adding an extra gasket under the fuel pump stand at the intake
has the effect of shortening the rod and lowering fuel pump pressure.
You can add one or 2 extra gaskets and experiment.

Don't ever grind the fuel pump pushrod to lower fuel pressure or push or stroke at the fuel pump as this is not easily reversible and over time the mechanical fuel pump looses some of it's pressure at which point you can always pull one of the extra gaskets out.

Also, there are 2 different fuel pump pushrods lengths depending on your intake.

Check that yours is close to the below specs dependent upon aluminum or cast intake manifold.

52-9400-A Push Rod - Fuel Pump (V8-60hp) - Alum. Intake (5.625")

52-9400-B Push Rod - Fuel Pump (V8-60hp) - Cast Iron (6.375")



Back in the old days gaskets were relatively thick,
now a days gaskets are less then paper thin so you may have
inadvertently/unknowingly "adjusted" the fuel pump pressure
upwards by installing a paper thin gasket and you wouldn't
even know it until the needle and seat (float) are
over powered and flooding happens..


Extra gaskets are cheap,

...Cheap enough to buy a couple and still have money for your morning donut






.

Read post #5.

Sal
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