What should these be? The rebuild kit instructions tell me 15/16ths down and 7/16ths up. This is letting way too much go juice in the engine to let it idle right.

What are the correct levels?

 

You can download the carb instructions from Edelbrock.com.

 

Could be a fuel pressure issue. Edelbrock carbs don't like much more than 5.5-6 PSI. Many mechanical and most electric pumps put out 7-10 PSI.
Also, if fuel is dripping into the bores from the boosters, check the metering rods for proper seating. If they aren't able to be pulled down, it will drip fuel at idle.

 

Originally the problem was that it would idle great, but if you got on it giving it more that 1/2 throttle the crappy idle would happen, stink of unburnt fuel but eventually it would clear up after shutting it off for about 30min. I suspected the accelerator pump was bad so I bought a rebuild kit and replaced it. While I was there I checked the float levels and tweeked them according to the instruction sheet, put it back together and it was worse than before. As for the electric pump, yes the P.O put on a Carter elect. pump and I suspect its putting out 7psi. I think that's what I saw on the label. I'll have to crawl under it tomorrow in the daylight and check that again. I'm not against restoring the mechanical pump, that would actually be my preference anyways.

 

It won't change. The specs for a mechanical pump on the 351M and 400 as well as most FORD engines of the era is 7 PSI.

Holley's have different float arm length to float volume ratios than Edelbrock carbs. A Holley because of it's larger float will shut a inlet needle against higher fuel pressures. A Holley wil live happily with as much as 8 PSI.

Edelbrocks will NOT handle 8 PSI or even 7 PSI. The book says 6 PSI max and the recomendation is 5.5 PSI max. Playing with float levels won't help much if that Carter is pumping 7 PSI and a mechanical pump that is working properly will likewise over whelm the inlet needles.

Don't waste money on the Mr Gasket or Spectra pressure regulators, get a decent one, like the Holley 12-803 Fuel Pressure Regulator ($30) and get a simple "vacuum and fuel pump pressure test" gage ($15-20 max, and it'll come in handy as a tool from now on) and use a tee in the fuel line between the FPR and carb to insert the gage for setting the FPR, then remove the tee and hook FPR straight to carb. The Holley FPR will supply enough fuel and maintain steady 5.5 psi at all times. There is no need for a gage staying under the hood unless you just "like it".

The Mr Gasket or Spectra will not consistantly hold pressure settings nor will they supply enough fuel to meet all demands with consistancy.

 

Thanks for the info. That sounds like the way to go on this. Im going to look into getting the Holley FPR. I really dont want to be messing with the float levels. I have a hunch the PO adjusted the floats to compensate for the increase in pressure because the floats hung down over an inch. But then again.....based on things I've discovered on this truck, he didn't know squat about basic engine tuning. IE....firing order was honked up, vacuum lines were everywhere and some weren't even hooked up. Again....thanks for your invaluable help.

 

I can comfirm that more than 5.5-6 PSI will cause an edelbrock to run a bit too rich.
I have an edelbrock 600 on one of my cars, and it has a cheapo electric pump with a PSI guage right before the carb. On a cold start, the guage reads 6.5-7 PSI, but after the engine has run long enough to warm up, the pump has also warmed up a bit, and the PSI drops to around 3 PSI. During engine warm up, without the choke being used, the carb loads up a bit causing minor black smoke to come out the exhaust. Once the engine (and fuel pump) are both warmed up and the PSI drops, it never has any issues. It can idle for over 20 minutes without black smoke, but by that time the PSI has dropped to almost nothing. Like I said, it's a cheapo pump, and it's plumbed in the "deadhead" manner.
I've swapped a holley carb on this same engine, and it doesn't suffer from the same black smoke issue when cold.

 

I never woulda thunk it. Thanks to everyone for helping me with the over pressure issue. Got the Holley FPR in the mail today from Summit Racing (kudos to those guys), got it all plumbed in and looks nice under the hood, tweaked it down to 5.5psi and life is good!! Idles nice......drives and accelerates nice. Feels good to finally wrap up a project.

 

[QUOTE=79F150400M;10527395]I never woulda thunk it. Thanks to everyone for helping me with the over pressure issue.

Thank you for the reply! People ask questions, and get lot's of advice from Guru's. By that I mean people with high knowledge in a particular area of expertise. Few OP's post back what the solution to their problem was. KUDO's to you!

Trust me here, I repair/troubleshoot many issues for my neighbor's. After a couple of month's, I get to hear how they diagnosed\repaired the issue all by themselves from other neighbors.

 

Thanks for the update!

I had just gone through the same deal a couple months ago, swapping out a 600 Holley for a fresh Edelbrock and having the same issues.

This FTE is a "good place" for info, the other posters make it so.

 

Certainly good to hear the issue has been resolved. I plan to upgrade to a 4bbl intake and carb using the edelbrock 600 I already have. Guess this means I'll need to also use the holley FPR I have. I'll put the PSI guage on it too, for tuning, then likely take it back off.
I had suspected the fuel PSI was the reason behind that car running too rich when cold, since I have the manual choke version of the 600, and don't have the choke hooked up, just a throttle spring to hold it open.

FTE is certainly a great place. No one can expect to know all the answers themselves, but as a group, I think we can cover most anything.........

 

I will always try to post back when a resolution has been found. I read lots of threads here and usually the OP doesn't come back and say what was causing the problem and i too, find that a little frustrating. This is one of the most informative and helpful forums that I frequent. I am a member on 2 or 3 others and those boards don't seem to move much, or the same question gets asked over and over. I certainly enjoy the sharing of information and a sense of camaraderie here on FTE.