Why do I have high fuel pressure...

[CHANMADD]

So much ado about nothing. Why ...tell me why...for what reason do you have two pumps........Why?????

[patrickt]

Originally Posted by CHANMADD

So much ado about nothing. Why ...tell me why...for what reason do you have two pumps........Why?????

I think Steve said it was because that's the way it came from KMH but, regardless, it really isn't that unusual to have both. The real concern I have now is that we're eating up the flywheel teeth.

[dcdoug]

Originally Posted by CHANMADD

So much ado about nothing. Why ...tell me why...for what reason do you have two pumps........Why?????

The originals had an electric fuel pump and a mech fuel pump set up in parallel with the electrical fuel pick up being lower in the tank. The originals didn't have a fuel level gauge, just a fuel pressure gauge. So you drove the car off the mech pump and if you ran out of gas, you flipped on the electric pump and either pitted or drove to the nearest gas station.

The 4000/6000 CSX cars are all still set up this way, even though most of us have fuel level gauges.

I've actually needed to use this feature....

[steve meltzer]

I probably won't get to the carb today, we'll just have to see. At any rate, my KMP (#174) has never had a fuel level gauge. Most Ferrari street cars until the late '60's, had both mechanical and e-pumps. Once I stop chewing starter and flywheel teeth, i'll be glad I had both. steve

[steve meltzer]

OK, Got out of school early today and you can't remove the primary bowl without...well I take that back. I didn't realize that you can get the primary bowl off if you just loosen the carb and lift it up a bit, as the accelerator pump arm sits in a groove in the Kirkham pan. I learned this after a bunch of extra work. Oh well.

So here are 2 photos of the bowl, its float (which looks low to me, but did have a "trickle" from the sight hole with the e-pump on), the PV and it's gasket and the metering block with its gaskets as I had it mounted. In the photos, the new PV gasket looks like it's been damaged, but it's fine and new as well. The photo lies. The PV was pretty snug. I'm sending the other 2 photos in a separate post.

thanx steve

[steve meltzer]

not sure why it posted a double take, but here are the other two photos i wanted to post. thanx again. s

[patrickt]

Originally Posted by steve meltzer

So here are 2 photos of the bowl, its float ... which looks low to me,

I can find nothing wrong in any of the pictures. That picture of your bowl also looks fine (because there's no gas in the float bowl to make it rise). To reassure you, here's a picture of mine, which is properly calibrated, although you can not tell it from the picture.



The only way I know to test a Power Valve is with a vacuum pump and something like the Moroso tester. But you can push the plunger back and forth with your thumb and finger and try and feel something different from the old one. I think I would just put the old one back in for now -- we're pretty confident it was working alright and if the new one is "stuck" in the open position, that could contribute to an overly rich mixture. An open Power Valve generally boosts up the circuit by a good ten jet sizes, which is quite a lot.

[steve meltzer]

Right, but mine also looked low when held upside down, as the factory says to set it dry. More later. s

[patrickt]

Originally Posted by steve meltzer

Right, but mine also looked low when held upside down, as the factory says to set it dry. More later. s

Alright. There is an old trick that you can use if you really think something is misbehaving between the float mechanism and the N/S valve, but it only does it when you have the bowl screwed on. The only reason I know this factoid is because of the configuration of the secondary side of the 4160. You probably wondered to yourself "why is the float in the secondary side black nitrophyl and the float on the primary side brass?" The reason is not that Holley wanted to cut corners; it is, instead, because a brass float will interfere, sometimes, on the metering plate on the secondary side of the 4160. You can't tell this, of course, when the bowl is off the carb, because there is no interference and everything works perfectly. The way you can check a float in that situation, is with dental floss. You tie the floss around the float and fish it out of one of the top bowl screw holes. You then put the bowl back on with three screws and you can test the operation of the float by pulling the floss. You can also blow in to the fuel line and, if your lungs are strong, you can muster a good 2.5psi to see that the N/S is indeed closing. As I said, this is a rarely used trick, but you now have it in your back pocket just in case you need it.