Tuning a Proform/Holley carb, what parts and tools?
Didn't make it to the show, cranked fuel pressure back to 4psi on the guage. Went and bought a new air filter, and the carb soaked it in gas the first mile.
Well that sucks, or rather blows. Several times I had to bleed off fuel from the bowls on the side of the highway.
Trash in the needle and seat?
Floats too high? (just above middle, but lower tha they were out of the box)
One of these or the regulator. Remember there's no pressure in the bowl (well atmosphere but you know what I mean). Can't be the gage other than possibly misleading you on the regulator setting. For some reason the fuel level by the sight glass looks right at idle and is overfilling with only what? a few hundred or 1000 rpm increase.
Don't think iI blew the PV because the mixture screws are still responsive, but I wiil swap a new one in tomorrow, anyway, card says it has a 6.5 in it. I only get about 9" of vacuum with this cam, which PV should I try? Could the 6.5 be part of my problem?
In reverse order:
No. Even with no power valve, it would be bleeding fuel into the base of the carb direct to the intake. Only way its coming through the bowl vent is overfilling. It's probably pouring out the main boosters as well.
I mean I guess if there was no squirters on the accelerator pump passage it would squirt up into the air cleaner but that's grasping at ideas when it seems like you've seen exactly what is happening. Why is the question.
I've limped my wagon back to my garage using gravity feed for fuel to bowls. That's all it takes to keep a carb bowl full at low throttle. So there's a possible test since you had it blow out the vent just revving it in the driveway. You'll have to get a little siphon action going. But
if you do this, obviously take your time on the setup and BE CAREFUL.
Power valve selection. Opening simply adds another path for fuel into to the main system. The idle system picks up fuel from the main. The idle restrictions are (normally) much smaller than the main restrictions so flow in the idle system is not normally effected by the power valve being open or closed.
Power valve opening point will be something less than cruising vacuum. Cruising here meaning being interstate speeds. My current setup cruises around 17-18"Hg so I'll use that as an example. Opening the throttle a bit drops the vacuum. If it accelerates well at 12"Hg but starts to flatten out at 10", then a 10.5" PV would be appropriate. If it doesn't flatten out until 6", then a 10.5 would probably make it more sluggish when part throttling from 7-10"Hg. In the
Holley Carburetor and Manifolds book there is a section on testing this by 'crowding' a vacuum. This sort of trial and error testing is about the best most of us can do.
