• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

Quick fuel carb issue

Bigal75 said:
And there's no way you want a 2.5 power valve on there. Go for a drive with a vacuum gauge and see what the gauge reads on a flat road while cruising in high gear. I bet it's a lot higher that 5" or 7". I'm guessing 12 to 15, so I would try a 10, 9 or 8.5 PV. And no it won't screw up your idle
Click to expand...
This what I’ve been trying to say in my post. I think the valve is being held open at idle.
 
I would start from the beginning again if i were you.
Set your initial timing lower, 12-15 deg to begin with. (high initial timing figures normally work well with lean idle conditions, when it is running very rich the combustion process is fast and peak pressure is happening at the wrong moment, which causes the engine to work against itself)
Open the idle mixture screws 1-1/2 turn, connect vacuum gauge and timing light and start from scratch.
If it continues to run seriously rich the power valve might cause trouble as mentioned already.
Stick a 5.5 or 6.5 power valve in there for the time being, i am guessing there is not much road testing with the car running as it does now, so for the time being there is no real point of being 100% on the power valve as this is not used for idle.
Once you get it to idle well, you can start road trial and check your vacuum during driving to see what power valve will suit the application.
That cam probably will require some rpm at idle to run, so maintaining an idle of 900-1000 rpm is nothing crazy.
 
chargermll said:
I'll try to explain this the best I can. For the past couple of months I have been getting my 72 Charger back together. I have a 950 QF carb on my stroked 440. This is a brand new carb that I put on my brand new engine. I did the general tune and fired the engine up. The only issue I had with this carb was that it was rich at idle. I played with the IFR's and IAB's to try to fix that issue. It got better but not perfect. I decided to try a smaller IFR. Did that, put the carb back on and now I can't get it to idle. Took carb off, put back to previous set up. Still having same issue. I double checked that my transfer slots were "squared" on both the primary and secondary. Double checked float levels. Both in the middle of site glass. I cleaned everything with carb cleaner and blew out the passages with compressed air. My timing is at 25 degrees initial. Changing timing has very little effect. The engine starts fairly easy and I can keep it running if I keep my foot on the pedal but its rough and dies as soon as I let off. I discovered that I can get it to idle( but very poor) if I pull the pcv hose off and create a vacuum leak. What I found out after doing this was that if I turn the idle mixture screws in the completely on the primary it has no effect, engine keeps running. If I turn the screws in on the secondarys then the engine shuts off like it should. So I'm thinking some how gas is leaking into the primary. I tried cleaning the primary's again. No change. I have an electric fuel pump. I have it set at 6 psi according to the gauge. I dropped it down to 4 psi and still no change. At this point I'm out of ideas. I'm sure this is something simple that I am just missing. I'm open to any ideas. Thank you
Click to expand...

The carb idled before, you went inside the carb, and now it does not idle. With 95% certainty, the problem is likely something that you touched.
 
chargermll said:
Just an update. I did a rebuild on my Quickfuel carb and still have the same issue. When I ordered my Quickfuel kit, I also ordered a rebuild kit for an old 850 double pumper that I had. Installed the rebuilt 850. Other than chasing a few gas leaks that carb is working great. I am going to call Holley some time next week and speak to them about the issue I was having. Maybe I can send it to them and have one of there experts look at it.
Click to expand...

You're wasting your time calling Holley,go to the source.Call Angela Neely at https://www.facebook.com/ATMInnovation/
.She is the daughter Marvin Beniot the founder of Quick Fuel,worked with her father for 15 yrs,running same operation on a smaller scale.
 
I re-read your initial post and am wondering if you have a wideband o2? Also do you have pics of the IFR installed and what's the size of the IABs?

I doubt you're pulling fuel from the main circuit unless you can physically see it happen. That circuit shouldn't be active at 1000 rpm.
 
Bigal75 said:
I re-read your initial post and am wondering if you have a wideband o2? Also do you have pics of the IFR installed and what's the size of the IABs?

I doubt you're pulling fuel from the main circuit unless you can physically see it happen. That circuit shouldn't be active at 1000 rpm.
Click to expand...

True, if the power valve leaks or fuel is pulled from the main you would see it if you look down the venturi.
Wideband O2 is a great help sorting this stuff out!
 
BSB67 said:
The carb idled before, you went inside the carb, and now it does not idle. With 95% certainty, the problem is likely something that you touched.
Click to expand...
I won't argue with that. I'm certain it was something I did. I just can't figure it out
 
Bigal75 said:
And there's no way you want a 2.5 power valve on there. Go for a drive with a vacuum gauge and see what the gauge reads on a flat road while cruising in high gear. I bet it's a lot higher that 5" or 7". I'm guessing 12 to 15, so I would try a 10, 9 or 8.5 PV. And no it won't screw up your idle
Click to expand...
I actually took the car for a quick drive around the neighborhood today. I can't go too far because the car isn't inspected yet. Your right, just cruising at around 30 mph I was getting around 12 to 15. This was with the 850 DP. At one point with the Quick fuel carb I went up to a 4 power valve, then took the power valve plug out of the secondary block and installed it in the primary block and still no change. For now I am going to leave the 850 installed so I can get the car inspected and street legal. I would like a solid two weeks of not having to drain a fuel bowl. lol
 
Wietse said:
I would start from the beginning again if i were you.
Set your initial timing lower, 12-15 deg to begin with. (high initial timing figures normally work well with lean idle conditions, when it is running very rich the combustion process is fast and peak pressure is happening at the wrong moment, which causes the engine to work against itself)
Open the idle mixture screws 1-1/2 turn, connect vacuum gauge and timing light and start from scratch.
If it continues to run seriously rich the power valve might cause trouble as mentioned already.
Stick a 5.5 or 6.5 power valve in there for the time being, i am guessing there is not much road testing with the car running as it does now, so for the time being there is no real point of being 100% on the power valve as this is not used for idle.
Once you get it to idle well, you can start road trial and check your vacuum during driving to see what power valve will suit the application.
That cam probably will require some rpm at idle to run, so maintaining an idle of 900-1000 rpm is nothing crazy.
Click to expand...
 
When I first started having this problem, Adjusting the timing had very little effect. If I retarded it too much then it would barely start. When it would start and I kept my foot on the gas pedal to keep it running, the idle was really rough. I rebuilt an old 850 DP I had and now the car is running good. I still need to get it inspected so I can legally drive it on the road. Once I get to that point I will tinker with that Quickfuel carb. I tried the power valve plug in the primary metering block and I was still having the same issue. I forgot to mention in another post that I will go to a higher power valve just to see if anything changes.
 
Bigal75 said:
I re-read your initial post and am wondering if you have a wideband o2? Also do you have pics of the IFR installed and what's the size of the IABs?

I doubt you're pulling fuel from the main circuit unless you can physically see it happen. That circuit shouldn't be active at 1000 rpm.
Click to expand...
No, I don't have a wideband o2. The IAB's are the 70. That is what was installed from the factory. I think the IFR's from factory were 36's. At one point I had smaller IFR's and larger IAB's. I put it back to the factory settings when I started having this problem. I can get you a pic later.
 
That’s a big cam in a big motor. Ideally you don’t want any transfer slot showing in the secondary and very little to none on the primary. It probably needs some bypass holes in the throttle plates. I even had to go the route in my 4150/1050 on my 511. I would also move the IFR’s to the low position, .034 is probably a good starting spot. And being a QF, it’ll probably need a transfer slot restriction for a clean cruise. IAB bleed is close, I’d go down to a .028 on the MAB to start. PV has absolutely no effect on the idle unless it’s leaking or blown. Verify it doesn’t have fuel running out of the boosters at idle.
 
Bigal75 said:
I re-read your initial post and am wondering if you have a wideband o2? Also do you have pics of the IFR installed and what's the size of the IABs?

I doubt you're pulling fuel from the main circuit unless you can physically see it happen. That circuit shouldn't be active at 1000 rpm.
Click to expand...

IMG_20190519_180517025.jpg IMG_20190519_180520423.jpg
 
chargermll said:
View attachment 769072 View attachment 769073
Click to expand...

Looks like a metering block, can’t diagnose your problem with that. There are 2 things I would change but it’ll require a 6-32 tap and brass set screws. I’d plug the middle emulsion (won’t fix your idle) but will help the cruise. I would also move the IFR low so it stays submerged. (Gives better idle quality) .

Same kinda block, just purple.

970CFF36-9273-4364-BA87-CC26C5A0B872.jpeg
08CBC480-F32D-482F-9AD8-16441D79731A.jpeg
 
^ I wanted to see if the idle fuel restriction was relocated to the bottom of the block.
 
Last edited:
Hoping this will help. My car ran fine with a 750 race Demon for years. A few weeks ago, I drove it around, came home, parked in front of the garage. When I went to pull the car in the garage, it wouldn't stay running. Popped, and backfired. Rebuilt the carb. Cleaned everything, and put in a new set of gaskets, and power valve. Same problems. I read this thread, and went out, and put in a new power valve, and it started up, and ran fine. So, I had 2 power valves in a row go bad. The quality of products is really bad anymore.
 
furyus said:
Hoping this will help. My car ran fine with a 750 race Demon for years. A few weeks ago, I drove it around, came home, parked in front of the garage. When I went to pull the car in the garage, it wouldn't stay running. Popped, and backfired. Rebuilt the carb. Cleaned everything, and put in a new set of gaskets, and power valve. Same problems. I read this thread, and went out, and put in a new power valve, and it started up, and ran fine. So, I had 2 power valves in a row go bad. The quality of products is really bad anymore.
Click to expand...
Thats a possibility that I might have some bad power valves that are bad out of the box. I thought when I installed the power valve block plug in the primary and I still had the same issue that would have ruled out that possibility. I will still try a higher rated power valve when I start messing with that carb again. I need a break from that carb.lol
 
68 HEMI GTS said:
Looks like a metering block, can’t diagnose your problem with that. There are 2 things I would change but it’ll require a 6-32 tap and brass set screws. I’d plug the middle emulsion (won’t fix your idle) but will help the cruise. I would also move the IFR low so it stays submerged. (Gives better idle quality) .

Same kinda block, just purple.

View attachment 769108 View attachment 769109
Click to expand...
If I get my carb issue figured out, I will definitly look into those mods you suggested. From your previous post, I really had to go bigger on the IAB and smaller on the IFR just so my eyes would not burn when the car was idling.(when it was working). What is an MAB? Is that the same as the High speed air bleed?
 
chargermll said:
If I get my carb issue figured out, I will definitly look into those mods you suggested. From your previous post, I really had to go bigger on the IAB and smaller on the IFR just so my eyes would not burn when the car was idling.(when it was working). What is an MAB? Is that the same as the High speed air bleed?
Click to expand...

Yes MAB is the inner bleed. Sometimes referred to high speed bleed
 
You must log in or register to reply here.

Similar threads

HAHNAGON
EDELBROCK CARBURETOR fuel sitting on secondary boosters ... wet secondaries?
Replies
10
Views
813
Dragon Slayer
D
68Zero
Help Carb Removal for Cleaning
Replies
18
Views
750
MWbirdLOVER70
MWbirdLOVER70
67Survivor!
Another Carb Question
2
Replies
28
Views
2K
Geoff 2
G
Tony 70GTX
Carter AVS 4737S 1970 GTX 440 4BBL
2 3
Replies
40
Views
3K
Some Car Guy
S
1967 satellite
Inline tube fuel lines
Replies
16
Views
936
mmissile
mmissile
Auto Transport Service
Back
Top