Idle Feed Restriction Size?

[PurpleBeeper]

What is the stock idle feed restriction size for 4382 & 4383 '70 outboard carburetors? I'm rebuilding the carbs right now & putting in Quick Fuel metering plates. The paperwork says the screw in idle feed restrictions that the plates come with are .039", but that I can change them. I'd like to go with the stock size hole.

Also, it sure looks like the Quick Fuel plates don't use the separator plate between the main body of the carb & the metering body. Is that right? Just leave out those separator plates?

Thanks for the help!

 

[62MAX]

If I remember correctly the idle feed is .037.
Did you get the cast or billet plate ? The cast plate is the same configuration as the O.E.M. and uses the plate.the billet does not as it is thicker and would interfere with the float.Cast plate top,billet on bottom.

 

[PurpleBeeper]

Hmmm.... well, I have the bottom billet plates. I've heard both ways "clears" & "won't clear" the floats. I will make sure to check the clearance carefully. I guess I need to see if Quick Fuel has some .037" idle feed restrictors.

 

[PurpleBeeper]

If I remember correctly the idle feed is .037.
Did you get the cast or billet plate ? The cast plate is the same configuration as the O.E.M. and uses the plate.the billet does not as it is thicker and would interfere with the float.Cast plate top,billet on bottom.

View attachment 334724 View attachment 334725

I test-fitted my thick, red Quick Fuel plates with a plate to main body gasket, jets & floats installed to check for any clearance problems. I looked very carefully & the floats (stock black plastic type used in outboard carbs) clears everything just fine. I am not using the separator plate & extra gasket like the stock metering plates use. I "think" the thick Quick Fuel plates don't use those (just metering plate & large blue main body gasket). Is that correct? I haven't seen anything "for sure" about leaving the separator plate & separator plate/metering plate gaskets out when using the Quick Flow metering plates.

 

[62MAX]

Separator plate and extra gasket only with cast metering plate,billet uses only main body gasket.

 

[440+6]

I have the Billet plates in my outboards and they clear just fine. No plate on mine.
I thought the stock idle feed restrictions where 029, (from memory so not positive ) I bought some brass plugs and drilled them out myself.

 

[62MAX]

Stock plates are .029 on big block,.043 on TA/AAR.Q/F plates are .037

 

[PurpleBeeper]

Stock plates are .029 on big block,.043 on TA/AAR.Q/F plates are .037

View attachment 335886

Thank again 62Max! I just ordered 4 .029" idle feed restrictors from Quick Fuel for $5. I had to call them since it's not listed on their website. I'm just waiting for my #77 jets to arrive for one side of the back carb. This will put all my orifices back to stock specifications & hopefully I can tune out this super-rich condition from there. From some stuff I read online, leaving those larger idle feed restrictions in the Quick Fuel plate would have left me still very, very rich at idle. I think those plates are designed for 3310 4-barrels.

 

[Polara1974]

Hi! I'm having the same issue with my 340 Six Pack carbs. I installed the QF billet metering plates front and back and put #77 and #70, left-right respectivelly. But the idle feed restrictors are at 0,039 on both plates.
I was under the asumption that the cast plates had 0,029 on Small blocks also. So the correct size is 0,043??? Kinda make no sense beeing bigger on the 340 vs 440. I need to go back, check my plate numbers and compare to the list posted by 62MAX.

So the only way to get thos idle feed restrictors with 4-40 thread is at Quickfuel? Do you have a part # PurpleBeeper?

 

[62MAX]

Hi! I'm having the same issue with my 340 Six Pack carbs. I installed the QF billet metering plates front and back and put #77 and #70, left-right respectivelly. But the idle feed restrictors are at 0,039 on both plates.
I was under the asumption that the cast plates had 0,029 on Small blocks also. So the correct size is 0,043??? Kinda make no sense beeing bigger on the 340 vs 440. I need to go back, check my plate numbers and compare to the list posted by 62MAX.

So the only way to get thos idle feed restrictors with 4-40 thread is at Quickfuel? Do you have a part # PurpleBeeper?

There is another choice,Q/F can give you plates with whatever size idle feeds you want as long as they know ahead of time.

 

[PurpleBeeper]

Hi! I'm having the same issue with my 340 Six Pack carbs. I installed the QF billet metering plates front and back and put #77 and #70, left-right respectivelly. But the idle feed restrictors are at 0,039 on both plates.
I was under the asumption that the cast plates had 0,029 on Small blocks also. So the correct size is 0,043??? Kinda make no sense beeing bigger on the 340 vs 440. I need to go back, check my plate numbers and compare to the list posted by 62MAX.

So the only way to get thos idle feed restrictors with 4-40 thread is at Quickfuel? Do you have a part # PurpleBeeper?

Well, I just called Quick Fuel & told them the size I needed. They're not in their online catalog. They take a 0.050" allen wrench to install & I had to heat the heck out of one of them with a propane torch to get it out (other 3 came out easy). And yes, if you order directly from Quick Fuel, you can specify the idle feed restriction.

Honestly, the only reason I bought the Quick Fuel metering plates was because I couldn't find a stock front plate for my '70 carbs & I was trying to get back to stock settings.... I had no choice. I don't have the part number handy, but I think it's the same plate as goes on the back of a 3310 vac. secondary 750 Holley.