Carb related questions

Some very basic carb questions.... 

I have a mild ford 302 in my car, with a holley 600 DP carb. It was running a walbro 255 in tank electric pump, with an aeromotive regulator that was built for an efi pump on a carb setup. I could only get the pressure down to 9.5 psi which I know is too much. The car started, and drove around fine, but I never gave the car WOT as it has a new clutch/flywheel combo. I knew the pump would be way too much, but was hoping the regulator could kick it down to the proper range. It couldn't, and the oil quickly reeked of fuel.

The 255 was just swapped out for a 155, and the pressure is able to be adjusted lower than the 9.5 psi before. It's currently in the 6 - 6.5 psi range. What should this motor be seeing fuel pressure psi wise? Is the current 6 - 6.5 range solid? Alot of fuel came out with the oil change, and hoping to no longer see fuel in the oil....

6.5 should fine.  5-7 psi is acceptable.

6.5 is in the safe range. My Capri was happiest at 6 psi running a similar Holley on a crate 306.

I only have experience with side-draught Webers. They need 2 to 2.5 PSI to run properly, which is hard to get with just a regulator. I needed to switch to a low-pressure, high-flow fuel pump in addition to the regulator. 

In reply to dropstep :

Perfect, Thanks. 

When it was running 9.5 psi, assuming it was just too much and flowing straight into the motor?

You're right on the money with 6.5 lbs. 

Shawnb said:

In reply to dropstep :

 

 

Perfect, Thanks. 

 

When it was running 9.5 psi, assuming it was just too much and flowing straight into the motor?

It should have run like crap, too. 

Shawnb said:

In reply to dropstep :

 

 

Perfect, Thanks. 

 

When it was running 9.5 psi, assuming it was just too much and flowing straight into the motor?

That is exactly what is happening. Change your oil immediatly.

I find 4.5 lb's works very well on a double pumper. I also find that putting the regulators as close to the carb as possible the best,

FYI check your floats are not ful of fuel an that the seats are still working as well while you are changing the oil.

In reply to LanEvo : I’m going to shock you and everyone who “knows” about British cars. 

Buy an old fashioned SU fuel pump.  It works perfectly at that sort of pressure and volume.  

Now here’s  the twist.  SU’s need maintenance.  Once every oil change I slide a 1&1/2” piece of fine emery paper  1000 grit folded in half through the points. The cap protecting them is held on by a thumb screw so it’s actually designed to work this way.  

Then once a year I put a drop of engine oil on the Wear Point of the pivot spring.  

That’s it!  I’m going on my 5th decade with this pump and no problems  

In reply to wearymicrobe :

Again, I know almost nothing about carbs....

I have a new fi tech setup, which I will be using on whatever motor I build this winter.  For now, hoping this Holley 600dp can do the job. 

The oil has already been changed, and I will be doing it again shortly to make sure it’s flushed out. 

How would one “check the floats”?

With the air cleaner off there’s no fuel in the “round ports” and when you apply throttle you can see fuel sprayed in. That stops when the throttle is closed though. This is with the car off. 

Your Holley carb should have a brass slotted screw on each fuel bowl, on the right side. With the car sitting level, take those screws out (maybe one at a time).  The fuel height adjustment is on the top middle of the fuel bowl. The slotted screw is the lock, and the nut is the adjustment (loosen screw a little, turn nut, tighten screw. It'll spew a little fuel while you do it). The proper adjustment is so you can just see the fuel spilling out through the threads on the sight hole. If you pull the sight plug out, and it dumps fuel *all over the place* and you can't make it quit with adjustments, your float has sunk, and you need to replace it. 

Plus one on that.  Depending on the carb, it may have sight glasses to check levels.

Make sure your oil is fresh, gas washing can clobber a motor, ask me how I know.

I was assuming that it was an older carb.  

You know what happens when you assume. You make rapid and sometimes incorrect decisions based on partial information.