Okay I have a 66 Fury with a 318 poly in it. Im having some issues.

pump gas once and car starts easy- Idles fine. If I floor it fast to WOT there is a delay in reaction. Sometimes followed with a backfire through the carb. So by now I think I have blown 4 power valves. smells to be running rich at idle.

Tried adjusting the air/fuel mixture. seems If I turn one side all the way in, the idle speeds up a bit. turnign both all the way in kills engine. right now I have both out about 1 turn- thats where where it is smoothest.

If I take the car for a ride from a dead stop flooring it- it bogs and pops then goes. But when it goes it doesnt go well- sounds like it is misfiring and laboring to go. Letting off the gas usually causes the engine to die.

At one point you can smell it is rich even when driving. After it stalls, it starts right back up.


Heres what was replaced:
timing Chain
intake gaskets
points/ condenser/ plugs/ cap/ rotor
New Accell Coil
used Holley 2brl.

Engine is stock- Has stock 2 brl intake manifold. Cam looked good when intake was off. Adjusted valves (they were too tight when I got it). checked compression (all about 110). and am sure timing chain was on right.

Timing at 10 BTDC. Accellerator pump on carb adjusted properly. and giving a good shot. Jets are 77 if I remember correctly.

Need some ideas what to look at. I think its runing too rich sicne I can smell it and since turning one mixture screw in all the way makes it run better. What am I looking for?

One thing I am concerned about is the heat flap in the right exhaust is still there but there is no brackets on it and I cant turn it- I can only ASSUME it is open full time.

you should pull your valve covers and check valve lash. these old polys have adjustable rockers and these may not have been adjusted in a long time. the valves may not be opening enough if lash is way off. mine ran like a champ after this. backfire through the carb is usually a spark in the intake tract at the wrong time.double check your timing as well.

Yeah I already adjusted the valves. I did it to .015 for intake and .021 for Exhaust (If I remeber right). When I was adjusting them it seems they were WAY too tight when I started. There was NO clearance.

I'd open up that carb & at the very least check the float level & also plug wires/vacuum leak

Float level is good- Pulled the plug in the side and fuel just starts to dribble out.

I have had the carb open a few time to change power valves. When I got it tihad a bad PV gasket- I replaced that and the gaskets are all new- Everythign there seems good.

Ill recheck plug wires.

I dont think there is any vacuum leaks. New gaskets everywhere. I spray some carb cleaner around to make sure.

A few things. Float level should be where you don't get fuel out unless you move the car side to side and it just sloshes out. You really don't need it much higher on the poly.

I ran into a situation a couple years back where the guy would rev the engine in park/neutral and saw most of the symptoms you describe and it turned out to be a leak or problem in the vacuum advance in the distributer. Try unplugging that and see if it makes a difference.

Okay will give it a try tomorrow. I was plannign to plug botht he vac advance and the PCV hoses just to elimnate them. will report back.

I have searched alot here and seems alot of people are having similar problems but most either dont report back or dont find the problem.

You stated that you did'nt have any valve lash when you checked it.Make sure that you adjusted them in the right position.Valves closed=spring s are not compressed.And that 318 should'nt require much pump shot from the carb.If it is an original type carb you may have to bend the rod to change that.And check your idle screw,if it is turned in to far,the carb gets confused and pulls fuel from the idle circuit and the power circuit and it will run rich.I have seen distributors that when pulled out the shaft had alot of side play in the shaft and cause alot of problems.

Yeah I researched the method how to adjust the valves. Im sure I did them right- The valves were completely closed and still tight. It ran alot better after I adjusted them.

Its a holley 2 brl on there now. It has a pretty healthy pump shot so if the 318 doesnt like alot of shot, maybe that is part of the problem.

And I did pull the distributer to check it- Its tight. No play in the shaft.

its not from too large of accellerator pump shot. Joe keep searching & inform us when you discover it.

Okay here is the latest:

changed the plugs again and the wires.

Rechecked the point gap and adjusted it from .020 to .016

plugged both the PCV port and the vac advance port (there is another small port under the carb that was already plugged). Sprayed carb with cleaner and appears no vac leak.

I also pulled the power valve and installed a plug. while i had it open I double checked all passages were clear. all were good.

SO- its a little better but not much. Still running rich at idle. I took it for ride again and it ran about the same... felt like it was laboring. I took it down a bit longer of a street and just kept the pedal down to see what happened. It ran like crap til about 3k rpm then seemed to smooth out... then started to bog out and stalled. Either it flooded or the fuel pump is not pumping good enough (its new too)

so aside from the possible pump issue it appears that it runs too rich. The fuel shot looks really big but as far as i know there isnt an adjustment for that. Any other ideas?


the carb is a holley 4412 with size 73 jets in it.

How old is the gas in the tank? My poly did similar when I changed over to electronic ignition. I disconnected the vacuum advance and the problem went away.

fresh tank today but the last tank wasnt old.

have tried with and without vac advance hooked up... no change.

get rid of the points first.. use pertronix or MP kit.. then start over good luck dan

what do the plugs look like when you R&R'd them? Do you have another carb handy you could sub in real quick to try & narrow this down? Will it rev to 3K OK by opening the throttle by hand but has a problem hitting 3K on the road?

Um..okay at the risk of embarassing myself- It has a manual choke which is not hooked up. I basically leave it full open because it starts fine like that. I let the car warm up and then do my testing.

So the choke is FULL OPEN when I am testing. So that would make it LEAN if anyhting correct?

if so then I am looking at dropping the jet size