holley six pak problem

[70gtx]

hi guys,i got 440 running today. seems to idle to rich,adjusted floats,have no fuel visibly dripping from venturi. if i take it up in rpm to 1200 horn starts putting out fuel,is this to fast.engine doesnt seem to smooth out till about 3000 rpm.cam is 266 duration.at 1000 to 2000 rpm i can see exhaust richness coming out pipes.if my power valve was blown i could see gas running from venturi's ,right. or maybe i have an ignition problem. MSD6al ,timing idle at 14 right now. HELP.

[Fly Boy]

GTX, What do you have the four mixture screws set at on the out board carbs? Try setting them at 1/4 turn out if they are not there already. This will give you a rich idle mixture if they are open much more than this.

[carson]

A couple of hints.

The Holley's can take only 6 pounds of fuel pressure max, any more and you are forcing the needle off the seat. The pressure increases with RPMs.

Also check for trash in the needle and seat, does not take much to flood carb. Could be at idle, with something in the seat, it is raising the float level but not enough to puke it out the top. But when RPM come up pressure and flow raise level.

Is the problem happening with all carbs or just one? If its all three it points to too much pressure.

Let us know what you find.

[amoparguy]

Did you tune your power valve to your idle vacuum yet? If not, ditch the unmarked NAPA parts and get the right power valve from Holley. Look for their blue "no-stick" gaskets too, they will make the carb disassembly and reassembly go much quicker. Once you get the right power valve in there, see if it's still rich. If the idle mixture screws have little or no effect there are further mods that you can perform to improve idle quality when using long duration camshafts with a lot of overlap.

I went through the same thing getting my .509 cammed 440 with a 780 Holley to idle cleanly at a reasonable rpm. I spent some time discussing the problem with a Holley rep at the Nats last summer, his advice was very helpful. I'm sure the same principals apply to the 6-pack carbs too.

[jfs mopars]

My 340 6 pack could only handle 5 1/2 psi, any more than that and it would start to flood during cruise rpm's. It was fine at idle and at full throttle, just at cruise speeds. Holley adj. regulator did the trick. Check outbord carb's mixture screws as stated on earlier post. Approx. 1/4 turn max. each. Power valve could be your problem with rich idle, it will show no outword apperance that it is blown. Vacuum at idle could also be lower than PV's rating. Make sure PV is at least 2.0 " less than vacuum at idle in gear. Use vacuum gauge to set idle mixture screws to the highest vacuum reading you can get. (takes some patience!)

[70gtx]

THE carbs are not running over. but i will check pressure.the idle mixture screws on all carbs are at 1 1/4. i cant really see them making it run this rich though . i'll check vacuum tomorrow . thanks

[HOLESHOT]

Make sure all out board carbs are closed then, look at the power valve in center carb,do ensure all carbs fuel levels are correct not just the center carb.Leave all else alone until you try this.

[70gtx]

mix ture screws did make a big difference on idle.float level are all good now .she's still fighting me though.if you think you can help read my other post. thanks for all the help.

[mr.b]

HAVE YOU HAD THE CARBS OR INTAKE OFF THE ENGINE LATELY. CHECK FOR VACUUM LEAKS. IF SO DO NOT OVER TIGHTEN THE BOLTS ON THE CARBS. IF THIS DONT APPLY THEN THE PROBLEM MAY BE WITH YOUR CENTER CARB. DISCONECT THE LINKAGE TO THE OUTBOARD CARBS. USE FLASHLIGHT TO MAKE SURE THE BUTTERFLIES ON THE OUTBOARD CARBS ARE COMPLETELY CLOSED. THE OUTBOARD CARBS DO NOT EVEN FUNCTION OR OPEN UNTIL THE ENGINE HAS A LOAD ON IT, OR PLAINLY PUT YOUR GETTING DOWN ON IT. OUTBOARD CARBS WILL NOT OPEN WHEN IDLING OR REVVVVVVVVING THE ENGINE IN NEUTRAL. IF THESE THING ARE OK THEN ADJUST THE CENTER TWO BARREL CARB. CARB MAY NEED ADJUSTING OR CLEANING. CHECK AIR BLEEDS. HAVE YOU DONE ANY THING TO THE CARBS LATELY.