[scott-462]

I put on a proform 67214. Its an 850 DP four corner idle with replaceable air bleeds. It's running way to rich. Fouled new plugs after a few days of driving. It came with 80F 86R jets and a 6.5PV. I went down to a 75F jet and 4.5PV and put in new plugs. Last time I had a vacuum guage on it, it had between 8-10 inches of vac. After the change, fouled the plugs out again after a few days. Anyone running one of these carbs on a similar engine (in signature) to give me an idea on jetting and air bleeds?

[Chadmokc]

Quick Fuel Q850 carb.
Specs :
Primary Jet 76
Secondary Jet 84
Primary air bleed 70
High speed air bleed 33
Primary and secondary nozzles 33
Needle and seat 120
Power valve 6.5

461ci
RPM intake
KRE unported d ports
230/236 112 Comp hyd rlr cam
NGK FR5 spark plugs

I'd say a similar enough combo and mine is smooth like efi.

It did take a bit of massaging with a vacuum gauge attached while adjusting the 4 corner idle adjustments. I beellllieve I'm about .5-.75 turns out, give or take, on each.

Good luck

[steve25]

First off you need to pin down where it's running too rich, idle circuit? Cruse circuit? Or full throttle.
With the motor fully warmed up do you see fuel dribbling out of any of the boosters at idle?

Does closing off the choke little by little at warm idle make the motor pick up rpm?

[Skip Fix]

Not sure how the Pro Form body is but my Demon 850 came factory jetted way fatter than my Holley 850. Demon main bleed also let it start getting fatter as rpm on cruise increases whereas Holley was closer for my combination. Like Steve said you need a good wide band and maybe even a vacuum gauge input as you log to see what circuit you are in.

[scott-462]

Id say it's rich at idle. Strong exhaust smell. In fact, after a new set of plugs it only takes a few days to foul them. I live in a small town and just cruise. The majority of the time it's at idle or barely pressing the throttle as i rarely go faster than 30mph in my small town. Most streets are rated at 30mph...

[TCSGTO]

First make sure your throttle plates are properly adjusted by "squaring" the primary transition slot. You could try going up 3 sizes on your idle air bleeds. Also, the Proform/Quick Fuel base plates have a longer transfer slot than the Holley parts do and this can case richness at low speed cruising. Some of their main bodies have a threaded transition feed port to allow for a restrictor jet to be installed. If not it's not hard to tap it and install a restrictor. The feed port is usually around .110" and many have success using an .080" restrictor.

If you want to go deeper into the carb try blocking the 2nd and 4th emulsion feeds in the metering block. This will lean out the cruise/transition also.

You could make these changes one at a time and test. They are reversible so you won't be permanently altering the carb.

Once you get it set up better put the 6.5 or higher power valve back in. The 4.5 could cause a lean sag when you crack the throttle at cruise.

Those are good carbs and I'm sure once you get it dialed in you'll be very happy with it.

[scott-462]

I put in the 4.5 because I've read you divide your vac by 2 and install that size pv. Ive seen between 8-10 inches of vac before when I've had a gauge on it. I havnt checked it with this new carb though.

[TCSGTO]

The power valve won't deliver fuel at idle even if it opens. Fuel will only flow through it when the mains kick in. So installing a lower rated one will only delay fuel feed when you need it. I really doubt it's causing your problem.

Try this forum. You'll get some sound advice there from some really sharp people.
http://racingfuelsystems.myfunforum....fe36c82d269b57

Good luck & keep us posted on any progress.