Upgraded intake, cannot get carb in tune

[Bluemonster71RT]

  The wires leaned the fuel out a lot on the 770 so, great idea for that. Thank you.   I figured on trying the new carb anyway. Installed it last night and was able to get running and set for best idle and correct float level. I did not get to drive it last night but at first impression, the throttle response was excellent. It revved up crisp and fast. Today, after I found a carb to air cleaner stud that would work in this, I was ready to take if for a spin. Got it warmed up and now it revs like crap. It has a huge lean spot and chokes on the way up. So trying to move the car didnt work well because it starts choking on the lean mixture. I just don't get whats going on here.       

[Chryco Psycho]

the wire in the air bleeds will richen the mix through the idle screws allowing it to idle properly .
so now you are using a new QF carb & it bogs ? Probably needs a bigger squirter & or cam for the accelerator pump

[Bluemonster71RT]

So the wire restricts the air and makes the idle circuit richer but yet leaned out the full rich condition at tip in under load. Not sure how that worked out but I'll use it.  The QF carb boggles the mind on how it can be perfect on the first day and now needs bigger squirters which are 31's and thats what I moved down from to lean out the other carb. Everything is so damn finicky.   

[Chryco Psycho]

Think of it this way the carb / vacuum draws fuel from the side of a straw dipped into the fuel approx 1/3 of the way up the straw the more the straw is open at the top the more air is drawn in with the fuel , as you restrict the top of the straw more fuel has to be drawn in making the mixture screws more sensitive .
Each carb is its own beast , give it what ever it asks for to run best , the QF responds differently to air flow so it may need more squirter as it draws fuel in slower through the boosters .

[dodj]

Each carb is its own beast , give it what ever it asks for to run best

And it can cost a lot in little parts until you determine the best set-up. You buy some jets, some bleeds, some squirters, some pump cams....$$ 

[Brads70]

Each carb is its own beast , give it what ever it asks for to run best

And it can cost a lot in little parts until you determine the best set-up. You buy some jets, some bleeds, some squirters, some pump cams....$$ 

Over the years I've amassed quite a few carb tuning parts. Buddies often borrow my stuff to tune their carbs then simply replace what they used.  I bought a jet kit, a few squirters and power valves and the cam kit and gaskets. Then for the air bleeds I bought in bulk (10's I think?) blanks or the smallest size then drilled them myself.  I love the QF carbs , they are all I'd ever buy after working with mine.  Even behind the PV is a removable jet that I ended up opening up slightly. Just do one thing at a time to see how it responds. Having an AF ratio gauge is a must to IMO.
The next step really is FI but ......$$$$

[Brads70]

  I didn't see anywhere  if your running a fuel pressure regulator?  Just a thought?

[Bluemonster71RT]

Over the years I've amassed quite a few carb tuning parts. Buddies often borrow my stuff to tune their carbs then simply replace what they used.  I bought a jet kit, a few squirters and power valves and the cam kit and gaskets. Then for the air bleeds I bought in bulk (10's I think?) blanks or the smallest size then drilled them myself.  I love the QF carbs , they are all I'd ever buy after working with mine.  Even behind the PV is a removable jet that I ended up opening up slightly. Just do one thing at a time to see how it responds. Having an AF ratio gauge is a must to IMO.
The next step really is FI but ......$$$$
[/quote]

Yep, my friend and I swap carb parts often. Fuel injection is on my list too.  For an update, being refreshed this am, I started the car again and checked things out. Here are some small issues that happened from Friday night till this am. The carb to intake was loose a few ft-lbs, the accelerator pump had too much slack and the rear float was way too low. I get the torque on the nuts but how the pump spring and the float got way out of wack after making sure it was good is goofy. Heat I guess?

That did make the throttle snappy again. So I took it for a ride. Initially it goes lean at tip in for a second then its good from there even as the secondaries are opening it seems ok. There is a lean spot at cruise where I just holding speed at about 1500rpm/30-40mph I suppose that it could be the power valve is a 4.5 and I have 11in vac. I can swap to my 5 or 5.5 and see what happens. AND OR also change the cam on the accel pump but that wont help the cruise. @WOT its around 12.5 13.5 for best I can see while trying to drive. That seems right to me.  It was the first time that the tires lit up from a roll out and then standing on it. It would just squat and go with the 770 on it. So that was fun! I imagine if I can get the tip in good, it will light em up from a dead stop with no pre-rev. I don't think Ill be putting the 770 back on.   

[Chryco Psycho]

If you adjusted the rear float down there is nowhere for the fuel to go so after driving it & burning off some of the fuel it can be low easily .
the pump arm could bend , if there was a blockage in the passage it would hydraulic lock & could bend the arm , , there cannot be any play there or you have instant bog

[Bluemonster71RT]

Another update. I changed a few things one at a time to try and fix some issues mentioned in my last post. To get the light throttle tip in lean spot out I changed the pump cam to the blue one looking for a more volume shot and slightly longer duration. It made the shot very rich but that initial slow crack of the throttle was still way to lean. So that means to me that it was something that was happening just before the pump shot would come into play.  I changed the power valve to a 6.5 to see if it did anything for the steady mid RPM cruise lean condition. I know its not supposed to effect that but figured I'd try it. It didn't help. So I upped the primary jets 2 sizes. It did help very little for the lean cruise but then goes to rich anything before and after. So I'll put those back. 

Friday I was looking for a solve of the lean tip in and came across a post where a guy had the same issue. Turns out his timing was locked at 36 deg. When he unlocked it and reset everything correctly, it fixed his issue.  So I thought I may re-look at my timing. I had it at 20 initial and 38 total. I bumped it to 22 initial making 40 total. I wasn't sure if the engine would be ok with this but it seemed to like it a lot. I can probably do more initial maybe 1 or 2 degrees, but the 18 advance stop bushing is the smallest one MSD makes so I don't know if its safe to go over 40 total. Though the initial tip-in is lean its not pegged lean. It hits 15.5 for a second and then goes way to rich because of the blue cam. So that's good. The lean cruise is slightly better too but not by much. 14.8-15.7, When it touches the 15.7 it chugs for a second. I'm wondering if a air bleed change for that would help or there is something else that I can adjust. I can go richer on the idle but its already ideal I think.       

Overall the car does like this carb much better than the 770. I have that one I think to the best it can be but it seems so sluggish compared to the QFT 750. Though gas mileage is much better on the 770. I'm pretty sure I can get the QFT 750 tuned in right and get that close in mpgs too.

I'll keep posting updates (in case anyone is following this) as long as weather permits me to take it for rides. Winter is coming 

[Chryco Psycho]

Over the years I have learned not to look at the timing # I just give the engine what it wants & leave it there , if it is hitting 50* but makes better power & or milage that is what it gets .
different cams all operate differently , the chart is posted here , so add more fuel instantly with low total volume others like the pink cam add a lot total but nothing at initial tip in , white or black could help .
Yes I am following & interested 

[Bluemonster71RT]

Here is where I am at for this round of testing.  I added a white cam just to see what it would do. It pushes a lot of fuel! Way too much. I tried the #2 position. It was still too much too fast. Id didnt change or effect any of the other issues. Next I dropped the primary Jet size down 1 to #73. This change got rid of the overly rich section right after low speed cruise. I think its perfect. So that was good. Then I put the 5.5 power valve back in to see if that effects anything. Not that I can tell really. So I changed the White cam to the green. This put the initial a little leaner but still too much so I figured Ill now drop the nozzle size. I had a 35 in and placed a 31. I did not have a 32. This change made the initial launch nice. It feels better taking off not too rich and not lean. BUT now if I punch it from around 2000rpm, it goes full lean and stumbles but not from a dead stop. I'm thinking its the secondary or maybe this nozzle is too small and I need to go up 1 or 2. But Ill have to buy those
to try it out. Wouldn't it be out of the primary accelerator pump circuit at this point though?  Well I changed the cam on the secondary to red. Still leans out but then is way too rich so I guess it must be the primary nozzle. The secondaries were perfect before changes made today so unless those changed effected what the secondaries do?  Lastly, none of these changes are helping the cruise at low speed. Like 25-35mph still too lean. I am wondering if at this point I should follow the other power valve train of thought where it is said to use a PV that is 2 points less than idle. IDK. The problem is just off the idle circuit but before the power circuit. How do I fix that just a little? I'm talking 1 point more fuel on the meter to go from 15 to 14. At 15.5 it chugs 14 is good. If I can get that there. the rest is falling into place already.   Sorry for the long update       

[Chryco Psycho]

I am glad you are making progress !!
When you say it goes lean punching it at 200 I assume you are going to full throttle , if the launch is crisp at part throttle then I would be tuning the secondary  , no point in adding fuel at part throttle all the time if it si working well there .
Can you feel a problem where it goes lean just off idle before the power circuit starts or is it just a reading on the gauge , if it feels ok leave it alone , the power valve 2" under the idle vacuum In gear could help momentarily

[Bluemonster71RT]

I am glad you are making progress !!
When you say it goes lean punching it at 200 I assume you are going to full throttle , if the launch is crisp at part throttle then I would be tuning the secondary  , no point in adding fuel at part throttle all the time if it si working well there .
Can you feel a problem where it goes lean just off idle before the power circuit starts or is it just a reading on the gauge , if it feels ok leave it alone , the power valve 2" under the idle vacuum In gear could help momentarily

Yes at 2000 its too the floor. It cuts out first then crashes in with the goods. Just off idle I can feel the hesitation. It seems like its just on the tip of good and bad but fluctuates so its very noticeable but giving just a tad more peddle or load, its good to go. 

[Chryco Psycho]

try raising the float level a hair or you could restrict the jet bleeds with wire also , the wire might be the best trick