Why do I have high fuel pressure...

steve meltzer · #1 (**permalink**) 05-04-2017, 07:45 PM

I realized (while working on the 4160 from my '67 'Vette) that while you can raise the float level, and thus the fuel level, on the 4160 by turning the needle/seat CCW, the opposite isn't true...before you can drop the float, you must rock the car to empty the bowl with the sight plug out or else the float won't drop because there's too much fuel in the bowl. Then you can turn the N/S CW and thus decrease the fuel level. Duh! steve

patrickt · #2 (**permalink**) 05-04-2017, 07:49 PM

The way I do it (no jokes please) is to put a paper towel under the boosters and then put my mouth on the vent tube and blow down through it. Gas flows right out the boosters and drops the level quick as a flash. Easiest and quickest way I know.

steve meltzer · #3 (**permalink**) 05-04-2017, 10:25 PM

well, flash whomever you'd like, as long as you remember to blow, not suck. s

1795 · #4 (**permalink**) 05-05-2017, 04:17 AM

Quote:

Originally Posted by patrickt

The way I do it (no jokes please) is to put a paper towel under the boosters and then put my mouth on the vent tube and blow down through it. Gas flows right out the boosters and drops the level quick as a flash. Easiest and quickest way I know.

Patrick,

I cannot quite picture that process. Would you mind making a youtube video of that and posting it for us?

Seriously though, you do have a good ability to figure out how to address problem when confronted with them. Now don't let that go to your head.
:roll eyes:

Jim

steve meltzer · #5 (**permalink**) 05-05-2017, 07:04 AM

Patrick, i agree with Jim. Maybe post on one of the porn sites? Perhaps entitled, "Holley does Dallas"? s

patrickt · #6 (**permalink**) 05-05-2017, 09:46 AM

... precisely why I have not posted this little carb tip previously.

steve meltzer · #7 (**permalink**) 06-14-2017, 08:08 PM

it's been awhile and the Cobra is still sitting, waiting for its place in line. in the meantime, can you help with the 4160 on my '67 'Vette. I believe this started when I pulled the carb to fix a leak on the secondary side, but I'm not sure. I also replace the throttle/acceleration rod. New gaskets, sl change to the vent rod (on the primary bowl), which somehow got bent a bit. No other changes.

Doesn't leak, and the car runs great in all aspects, except if/when you "slam" the accelerator at idle. Then it stumbles and usually dies. I cleaned the pump squirter in lacquer thinner and blew it out with compressed air. It looks like there's a good pump shot if you just "flick" the accelerator rod or the arm, but not if you do it suddenly and with the force of "slamming your foot down on the go pedal". Then the shot is poor. Floats are perfect.

Timing is spec (base=10° BTDC) and the vacuum can works fine with a Mity Vac and, visually, with a timing light, it advances under acceleration. New dizzy cap.

I have not replaced the a-pump as I'm not convinced it matters, but should I? Would advancing the timing help? thanx. steve

patrickt · #8 (**permalink**) 06-15-2017, 06:08 AM

I would first check the accelerator pump. You have a 30cc pump in your 4160, which should be squirting a volume of 3cc on each good full stroke of the pump. So, run your car for a minute or so to get the front bowl nicely filled, then shut the engine off. Tuck a sandwich baggie (or some other suitable receptacle) around the squirter, get back in the car, and with the engine OFF give the accelerator pedal five nice, hard pumps to the floor. Pull the baggie of gas back out, trying not to spill it, and pour it in to your graduated cylinder. If you don't have 15cc's of gas in there then repeat the test. If you consistently fail this test, then you've found the problem and we'll figure out what's broken on that circuit.