Re: Jetting& Altitude
[Re: pjc360]
#1644685
07/11/14 02:58 AM
07/11/14 02:58 AM
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Joined: May 2008
Posts: 5,399 Aurora, Colorado
451Mopar
master
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master
Joined: May 2008
Posts: 5,399
Aurora, Colorado
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I think you went backwards on some adjustments from the original post? I would use the original restriction and bleeds, they sounded OK. Check vacuum in gear and use a power valve that is 1/2 or lower than that, so if you have 10" vacuum, use a 4.5 power valve. Once the carb is set at your idle speed, pull the carb and check that the throttle blades are not so far open they are exposing the transfer slot. A small amount of exposed transfer slot (so it looks like a square) is OK. If the transfer slot is exposed, you may be able the crack the rear throttle blades a small amount. I don't know it the carb has an adjustable idle air bleed? I usually have to drill the throttle blades to allow a bit of idle air through with the throttle blades don't expose the transfer slot. I would then just work on adjusting your jetting and accelerator pump.
I read through the rest of the posts. As I mentioned above, make sure the throttle blades are not too far open at idle, then the idle screws can be adjusted for the correct mixture. The spark plugs might also be too cool a heat range for your combination causing them to foul easier than they should.
Last edited by 451Mopar; 07/11/14 03:07 AM.
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Re: Jetting& Altitude
[Re: 451Mopar]
#1644686
07/11/14 09:17 AM
07/11/14 09:17 AM
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Joined: Jan 2003
Posts: 5,446 Indiana
YO7_A66
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master
Joined: Jan 2003
Posts: 5,446
Indiana
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You should not be fouling plugs that quickly.
- 451 has a good point: what plugs are you using? - 15 degrees initial timing may not be enough - If the .028 front IFR's helped out on the lean idle, then that is your hint to keep going that direction and maybe one of the above items is the actual reason as to why you are fouling plugs.
1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)
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Re: Jetting& Altitude
[Re: pjc360]
#1644691
07/12/14 10:07 AM
07/12/14 10:07 AM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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I was thinking the float level is supposed to be at the bottom of the sight hole? To where it would just spill if you rocked the eng slightly. From your last post it sounds like you ARE making good progress
live every 24 hour block of time like it's your last day on earth
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Re: Jetting& Altitude
[Re: pjc360]
#1644692
07/12/14 11:37 AM
07/12/14 11:37 AM
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Joined: Jan 2003
Posts: 5,446 Indiana
YO7_A66
master
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master
Joined: Jan 2003
Posts: 5,446
Indiana
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Nice job!!! If you need to lean it out any more in the future, then just swap out the .072 IAB's for some .075/.078's or something in that area then reset your in D idle vacuum again and test again. Do what you can to keep the four metering screws between 1/2 - 1 turn out. These QF carbs don't like much more than 1 turn. You now need to go out and drive it for a while to clean up those plugs. Have fun!
1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)
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Re: Jetting& Altitude
[Re: pjc360]
#1644694
07/12/14 06:03 PM
07/12/14 06:03 PM
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Joined: Jan 2003
Posts: 5,446 Indiana
YO7_A66
master
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master
Joined: Jan 2003
Posts: 5,446
Indiana
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Since you found improvement with the .031's, then retest with the .033's. You will need to reset your in D vacuum again. Then test with the different IAB's that you have.
Since the IFR's and the IAB's work together, look at the IFR's as your "internal adjustment" and the IAB's as your "external adjustment". If you have three sets of IAB's, then test with all three to see if it makes a difference. If the three sets that you have do not give you the results that you want, then open the carb and change the IFR's then retest with the three sets of IAB's again if needed. You usually want to change the IFR's in small increments (.002-.003" at a time). The IAB's can be changed in larger increments (.005" or so).
I would test your smallest IAB's along with the .033 IFR's. If your smallest IAB's are not small enough, then take a small wire and insert it down into each of the primary IAB's and bent the top of the wire so that it goes down into the carb body so it will not fall out. This will reduce the IAB hole and allow you to test a richer setup before buying more IAB's.
1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)
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Re: Jetting& Altitude
[Re: pjc360]
#1644696
07/16/14 12:30 AM
07/16/14 12:30 AM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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I would definitely get the LM1 & get the systems spot on in order. The carb tech given here is extremely good
live every 24 hour block of time like it's your last day on earth
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Re: Jetting& Altitude
[Re: pjc360]
#1644700
07/17/14 08:53 AM
07/17/14 08:53 AM
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Joined: Jan 2003
Posts: 5,446 Indiana
YO7_A66
master
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master
Joined: Jan 2003
Posts: 5,446
Indiana
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"" I'm running an orange accelerator pump cam/.035 squirter" - The ORANGE cam is the second largest 30cc pump cam. It is very aggressive off idle and "could" cause the black smoke at the blip of the throttle. Try using a less aggressive pump cam (white/black).
Check your power valve as noted. My NEW 10.5 QF power valve was bad and QF is who told me to check it!! Double check that you tightened down the IFR's. If they are not tight, the fuel would leak past them. I know that they are small but just make sure that they are snugged up. I am still guessing that "something" is leaking on you that is causing the fouled plugs since you have seen this since running the .025 IFR's. You have found that .025 & .028 IFR's are too lean, so maybe the .030's might help out a bit.
1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)
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Re: Jetting& Altitude
[Re: Cab_Burge]
#1644702
07/17/14 04:48 PM
07/17/14 04:48 PM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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What Cab said, most people tighten PV's too loose and jets too tight
live every 24 hour block of time like it's your last day on earth
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