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440-6 question - Almost stalls when stopping downhill ? #137763 10/16/08 07:46 PM 10/16/08 07:46 PM
Joined: Jul 2008 Posts: 157 California D dg_dodge OP member
dg_dodge OP member D Joined: Jul 2008 Posts: 157 California	Hello Six Pack carb guys, My 440-6 is running pretty good at the moment after having had the carbs recently rebuilt. It idles well and has no problems while accelerating or driving normally. The only issue I have is that when I go to stop at a stop sign or light when going downhill ...or when I have to brake to stop quickly ... I feel the car almost stall (rpms drop down and sounds for about a second or two like it almost dies), then it picks back up and is fine once I do stop. Again, this happens only when braking to a stop suddenly, or going downhill and coming to a stop. Otherwise, it's fine. Does this sound like the floats are not set correctly? If so, would it most likely be the Center that is doing this or the Outboards also? Or possibly something else? It's a 4-speed car, if that makes a difference. Thanks a lot for any advice!

Re: 440-6 question - Almost stalls when stopping downhill ? [Re: dg_dodge] #137764 10/16/08 08:07 PM 10/16/08 08:07 PM
Joined: Jan 2003 Posts: 9,826 las vegas 70AARcuda master
70AARcuda master Joined: Jan 2003 Posts: 9,826 las vegas	certainly sounds like the floats are too high.. even if the carbs are rebuilt and the floats were set dry, they need to be checked on the car. Tony 70 AARCuda Vitamin C 71 Dart Swinger 360 10.318 @ 128.22(10-04-14 Bakersfield) 71 Demon 360 10.666 @122.41 (01-29-17 @ Las Vegas) 71 Duster 408 (10.29 @ 127.86 3/16/19 Las Vegas)

Re: 440-6 question - Almost stalls when stopping downhill ? [Re: 70AARcuda] #137765 10/16/08 08:44 PM 10/16/08 08:44 PM
Joined: Jun 2008 Posts: 3,916 usa L lewtot184 master
lewtot184 master L Joined: Jun 2008 Posts: 3,916 usa	float levels in the end carbs are too low. when stopping the fuel is rushing toward the front of the float bowl uncovering the metering orifices. i usually set the float level on the end carbs with fuel up to the bottom of the sight plug hole plus 1/8 turn. if the idle mixture on the end carbs is too lean it will aggravate the situation.

Re: 440-6 question - Almost stalls when stopping downhill ? [Re: lewtot184] #137766 10/16/08 09:02 PM 10/16/08 09:02 PM
Joined: Nov 2005 Posts: 836 lancaster, new york macmic87 super stock
macmic87 super stock Joined: Nov 2005 Posts: 836 lancaster, new york	Quote: float levels in the end carbs are too low. when stopping the fuel is rushing toward the front of the float bowl uncovering the metering orifices. i usually set the float level on the end carbs with fuel up to the bottom of the sight plug hole plus 1/8 turn. if the idle mixture on the end carbs is too lean it will aggravate the situation.

Re: 440-6 question - Almost stalls when stopping downhill ? [Re: macmic87] #137767 10/17/08 12:51 PM 10/17/08 12:51 PM
Joined: Jul 2008 Posts: 157 California D dg_dodge OP member
dg_dodge OP member D Joined: Jul 2008 Posts: 157 California	Thanks a lot guys for the help on this! I will check out the float levels and readjust. One more question -- If I change the float levels in the end carbs, will I need to adjust idle mixture again (or other tuning steps)? Thanks much!

Re: 440-6 question - Almost stalls when stopping downhill ? [Re: dg_dodge] #137768 10/17/08 01:08 PM 10/17/08 01:08 PM
Joined: Jan 2003 Posts: 24,562 Brookeville, Md Mr.Yuck Not enough dumb comments...yet
Mr.Yuck Not enough dumb comments...yet Joined: Jan 2003 Posts: 24,562 Brookeville, Md	yup my 1st thought was floats

Re: 440-6 question - Almost stalls when stopping downhill ? [Re: dg_dodge] #137769 10/17/08 01:54 PM 10/17/08 01:54 PM
Joined: Jun 2008 Posts: 3,916 usa L lewtot184 master
lewtot184 master L Joined: Jun 2008 Posts: 3,916 usa	Quote: Thanks a lot guys for the help on this! I will check out the float levels and readjust. One more question -- If I change the float levels in the end carbs, will I need to adjust idle mixture again (or other tuning steps)? Thanks much! raising or lowering float levels can effect idle and main metering mix. for instance; if the idle is lean now, raising the float level may enrichen idle mixture. any adjustments may depend on where your at now with a/f ratio.

Re: 440-6 question - Almost stalls when stopping downhill ? [Re: dg_dodge] #137770 10/17/08 06:19 PM 10/17/08 06:19 PM
Joined: Oct 2005 Posts: 8,882 Ontario, Canada S Stanton Don't question me!
Stanton Don't question me! S Joined: Oct 2005 Posts: 8,882 Ontario, Canada	I realize the problem is solved but I'm curious ... The end carbs are vac. operated so they should be closed most of the time. Therefore they wouldn't have any affect on the stopping or downhill motion of the car. The center carb should be the only one having any impact on this problem ... no???

Re: 440-6 question - Almost stalls when stopping downhill ? [Re: Stanton] #137771 10/17/08 08:06 PM 10/17/08 08:06 PM
Joined: Jun 2008 Posts: 3,916 usa L lewtot184 master
lewtot184 master L Joined: Jun 2008 Posts: 3,916 usa	Quote: I realize the problem is solved but I'm curious ... The end carbs are vac. operated so they should be closed most of the time. Therefore they wouldn't have any affect on the stopping or downhill motion of the car. The center carb should be the only one having any impact on this problem ... no??? the real issue is that the end carbs have secondary float bowls facing in the wrong direction for proper fuel control. the float levels for the end carbs are about 1/8" lower than primary bowls. this would be o.k if the bowls faced in the opposite direction of a primary bowl. to my knowledge all 4150-4160 type holley 4 barrels use a lower secondary fuel level. the lower secondary level prevents fuel slosh out the venturis during hard braking in 4 barrels. the lower fuel level is necessary for metering plates but creates an issue when the fuel moves to the front of the bowl during hard stopping on 6-paks due to the bowl being designed to be used in the opposite direction. the main metering orifices need to be submerged in fuel at all times for the idle circuts to work. when the fuel sloshes forward the orifices are momentarily out of the fuel causing a lean condition and the engine wants to stall. the simple cure is to raise the float levels a little on the end carbs.

Re: 440-6 question - Almost stalls when stopping downhill ? [Re: lewtot184] #137772 10/17/08 08:13 PM 10/17/08 08:13 PM
Joined: Jul 2008 Posts: 157 California D dg_dodge OP member
dg_dodge OP member D Joined: Jul 2008 Posts: 157 California	Thanks much Lew for the great info and explanation of this issue. This will be the first time I've adjusted the float levels.. Is it recommended to take out the site plugs on the end carbs with the engine running to see if it's dribbling out the hole, or is this generally done with the engine off? Thanks a lot!

Re: 440-6 question - Almost stalls when stopping downhill ? [Re: dg_dodge] #137773 10/17/08 09:56 PM 10/17/08 09:56 PM
Joined: Jun 2008 Posts: 3,916 usa L lewtot184 master
lewtot184 master L Joined: Jun 2008 Posts: 3,916 usa	float adjustment needs to be done with engine running and sight plugs out.

Re: 440-6 question - Almost stalls when stopping downhill ? [Re: lewtot184] #137774 10/17/08 10:49 PM 10/17/08 10:49 PM
Joined: Jun 2008 Posts: 3,916 usa L lewtot184 master
lewtot184 master L Joined: Jun 2008 Posts: 3,916 usa	if this is the first time you have adjusted the floats then i must assume you haven't adjusted the idle circuts in the end carbs or checked the jetting in the center carb, right?

Re: 440-6 question - Almost stalls when stopping downhill ? [Re: lewtot184] #137775 10/17/08 10:50 PM 10/17/08 10:50 PM
Joined: Jan 2003 Posts: 3,683 South San Francisco, Ca 70sixpkrt master
70sixpkrt master Joined: Jan 2003 Posts: 3,683 South San Francisco, Ca	Quote: float adjustment needs to be done with engine running and sight plugs out I like to use the clear site plugs when doing this so fuel doesn't get all over the place. After you set the floats, just take them out and use the stock ones. [img]http://www.imgur.com/hxlGUJt.gif[/img] 4-speed 3:54 Dana 13.01 @107.93 with street tires (not hooking up)

Re: 440-6 question - Almost stalls when stopping downhill ? [Re: lewtot184] #137776 10/17/08 11:13 PM 10/17/08 11:13 PM
Joined: Jul 2008 Posts: 157 California D dg_dodge OP member
dg_dodge OP member D Joined: Jul 2008 Posts: 157 California	Thanks everyone for the help and advice. Lew - the idle and A/F in end and center carbs were adjusted when the rebuilt carbs were put on the car (not by me though). It looks like the one thing overlooked might have been the float settings when it was running... thus the "almost stall" condition I'm seeing now on sudden or downhill stopping. I'll find a set of clear site plugs as was suggested and see how low my current levels are. I'm hoping it won't be too far off so the adjustment doesn't change my current A/F or idle too much, as the car is running pretty well right now, other than this issue. Thanks again for the tips!

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