70vetteinpieces

I bought a new Edelbrock 1901 Carb for my slightly modified 350 - now 383
The old rochester ran well but leaked and had a few missing choke parts. Can I use the jets (metering rods) from that carb in the new edelbrock?

The car is running extremely rich - burning my eyes, sucks down the gas
and fouling out my plugs.

I am going to check the float level first.

Any other suggestions?

Disappointed that it didn't work well out of the box with just needing a little fine tuning

lars

The jets and rods will physically interchange, but internal calibrations on the two carbs are completely different: just beacuse the old jets worked well in your old carb does not mean that thay will produce the correct mixture ratio in the 1901. The 1901 should run well straight out of the box. If anything, I have found them to be jetted just a touch on the lean side (jetting in the 1901 is "truck carb" jetting). If the 1901 is extremely rich, you may have some other issue, like a power piston that is not seating, etc. Are you running the correct manifold base gasket? An incorrect base gasket can erode manifold vacuum, making the piston not seat and producing the results you are getting. Check your intake manifold and see if it is equipped with the curved exhaust crossover groove that runs from side-to-side just forward of the primary throttle holes - if you have this crossover, you have to use a special 3-gasket gasket pack: use of the gasket supplied with the 1901 will cause an exhaut leak into your intake and will produce the symptoms you are experiencing. Let me know if you need this gasket pack - I can get you the right parts. Also, tag me back if you get stumped on the problem and I'll be glad to help you out.


[Modified by lars, 10:51 AM 4/2/2003]

70vetteinpieces

Check your intake manifold and see if it is equipped with the curved exhaust crossover groove that runs from side-to-side just forward of the primary throttle holes - I never heard of that. will have to check that too

Power piston? Is there a way to check this?

Thanks


[Modified by 70vetteinpieces, 5:03 AM 4/3/2003]

1969c3mandy

quote:Can I use the jets (metering rods) from that carb in the new edelbrock?

No. I had the same problem with too rich. i leaned it out and still flooded (not really, but you know what I mean) at low RPMs, but ran like a raped date at high rpms.

You can buy a set of rods, jets and springs from any local parts store from edelbrock. For $40, don't **** with it. Now it's fine IMO.

oh, and I dumped the quadrajet for the performer series six months later.

mvftw

Mine runs alittle rich also, but since it's the factory carb, I'm going to send it to LARS from this forum...I have heard enough Good thing about him!

lars

70vette -
Yes you can check the power piston to see if it's stuck:
Take a long (need to be at least 2-1/2" long), very thin screwdriver (about 1/8" wide blade) and gently insert it down the bowl vent tube. You must angle the screwdriver slight forwards as you go down the hole. If you get the screwdriver angled forward down the vent hole, it will hit the top hanger of the power piston. With the engine not running, you should be able to push the power piston down against the spring pressure and feel it pop back up when you release it. With the engine running, the piston should be fully seated, and you should not be able to compress the piston with the screwdriver. If either of these tests does not produce those results, you have a power piston problem.

70vetteinpieces

I checked the float level and it was good. Also checked the piston and did the two tests and it's working properly.

I removed the carb and the intake is solid at the front - no exhaust hole - one like a big crooked smile. I am using the gasket that came with the 1901. Since it is open for all 4 barrels would that cause a problem? I sprayed wd40 around the edge and no vacuum leaks.

Next test I put an inline fuel pressure gauge in the system. Shocked at the results - It's a new AC fuel pump. At fast idle it's a steady 6 lbs. But when I kicked it off to normal idle, the pressure jumping all over the place and was spiking past ten lbs - I could hear the needle on the gauge hitting the stop.

Have a new pump on order.

Then I bypassed the mechanical pump with an electric pump. The pressure would very between 5-6 lbs. Sounds reasonable since I had no return line, and I heard the pump stop and start

However, It's still super rich with the electric pump. I took a white rag to cover the exhaust and it very quickly had a lot of black soot.

I wonder if the idle screws are wrong? I did adjust them a little to get the best rpm. Just wonder if I turn them in all the way then back them out a number of turns to get an inital setting?

Joe

lars

Initial bench setting for idle mixture screws on the 1901 is 2 turns out from lightly seated. Compare that to where you're at.