Excessive Fuel Pressure or Bad Carb?

[octanejunkie]

The previous owner of my 71 Scamp did a few upgrades planning on running the car, one of his mods was an electric fuel pump, an autozone special by appearance.

When I changed the oil on the car I got about 7+ quarts of black stuff with the consistency of milk out of the pan and it smelled like gas.

I did a compression test. Got around 120 psi on most cyls. Checked floats and cleaned carb out real good (Carter 4-bbl 9926) and checked fuel pressure - 8-9 psi from that electric pump.

I thought 4-7 psi was all that was required...

On one or two instances when test driving the car it has flooded, an actual puddle of gas on the floor of the intake manifold. All other signs like plugs, etc indicate an overly rich condition...

Is it possible that the fuel pump is sending too much pressure to the carb and overrunning the float valves or is the carb bad?

 

[1968FormulaS340]

You need to check the fuel pressure at the carb.

Usually you need an inline fuel pressure regulator with an electric pump. I bet that is your problem.

 

[Blownfish]

You need to check the fuel pressure at the carb.

Usually you need an inline fuel pressure regulator with an electric pump. I bet that is your problem.

I agree, and if you got that much fuel in the oil, it probably washed the rings so take some light weight oil and put it in each cylinder and let it work it's way into the rings before you run it again or you could cause some good damage to the rings and cylinder walls.

 

[octanejunkie]

You need to check the fuel pressure at the carb.

Usually you need an inline fuel pressure regulator with an electric pump. I bet that is your problem.

That is fuel pressure at the carb...

 

[POS Dakota]

That is fuel pressure at the carb...

yeah then it's too high.

6-7 seems to be the norm.

 

[1968FormulaS340]

That is fuel pressure at the carb...

Sorry…. I didn't see that you said 8-9 pounds of fuel pressure. Your fuel pressure is high, that's the problem.

 

[octanejunkie]

You need to check the fuel pressure at the carb.

Usually you need an inline fuel pressure regulator with an electric pump. I bet that is your problem.

Unfortunately a regulator costs more than an entire new pump... going the route of new fuel pump this weekend. At least the one in there is quiet...

I agree, and if you got that much fuel in the oil, it probably washed the rings so take some light weight oil and put it in each cylinder and let it work it's way into the rings before you run it again or you could cause some good damage to the rings and cylinder walls.

I squirted some Marvel Mystery oil in there and let it sit a bit before doing anything else. Truth is this engine is coming out as soon as my 360 magnum build is done, not too concerned about this block or the rings, but I did attempt to follow best practices by oiling the rings.