The Jalopy Journal

OldCarPilot · 12-20-2003, 05:18 PM

Just rebuilt a Holly 600. This is my first rebuild on a carb so I'm sure I've done something wrong. What is happening is the carb seems like its DUMPING fuel in. Its all comming out the back of the car in a cloud of gas. I changed the power valve to see if that would help. Seemed like it helped for about 5 sec then it was running too rich again. I can screw the idle screws in all the way and still runs like that.
Did I miss something obvious?

Fat Hack · 12-20-2003, 05:19 PM

Start with your float level adjustment, and also check to be sure that the needle and seat is not sticking.

Rocket88 · 12-20-2003, 05:23 PM

Sounds like you've got some crap in the needle and seat.

Model A Vette · 12-20-2003, 11:52 PM

Did the engine backfire (even once) after you changed the power valve? If you did not add the checkvalve kit the power valve could be blown again. The kit is a ball and maybe a spring that is added to prevent the power valve from blowing every time the engine backfires. Years ago my Camaro had some downtime because I didn't know about the power valve blowing due to backfires.

Hot Rod To Hell · 12-21-2003, 12:07 AM

If you have your idle speed set to high you will be running off of the MAIN circuit, not the idle circuit... the screws wont do anything if that's the case...

OldCarPilot · 12-21-2003, 02:13 AM

No back fires, and the idle is not too high. I've done a few diffrent settings to play with it.
I'll, now, play with the needle and see what I can find.
Thanks all for the info!

FEDER · 12-21-2003, 01:04 PM

OCP look on the passenger side of the carb at the float bowls.You will see a flat head screw one for the front, one for the back.
Remove the screws.
Look for fuel to come out.
If fuel is gushing out your float level is too high.
On the top of the bowl is another screw and 5/8" jam nut.
Loosen the jam turn the screw clockwise 2 full turns.
Now you have lowered the float.
Do this to the front and rear.
Leave the side screws out -start the car
Let it idle only.
Now no fuel should be coming out either bowl. If so.
Shut it off and lower the float some more-1 turn
Restart and slowly raise the float,untill you see fuel
just start to dribble out the side hole.
tighten up the float screw and jam nut.
Screw in the side screws.(sight plugs)

and repeat on the rear bowl.
WALAA you have just set yer float bowls so give it a try.
FEDER

OldCarPilot · 12-21-2003, 02:06 PM

Tried reseting the float. Biggest problem is I can't keep it idling long enough to set the float when its running. The car isn't "running rich" it is puffing fuel out the back in big grey clouds. Feels like a cylinder is not firing or something, but that is unlikely to be the case as the car was running fine with a (much newer) Holley 750 on it. I went though and checked all the plugs and cleaned them all up. Checked the needle and found no dirt or anything in there. Its like something is staying open spraying fuel down the carb. I can idle it long enough to let it run and look down the carb either. I have to keep my foot on the accelerator to keep it running. Bring the rpms up to about 1500, but it doesn't feel good. And then I just make a huge cloud of gassy smoke that I'm sure my neigbors love.
I don't know what the deal with it is.

Fat Hack · 12-21-2003, 02:33 PM

Possible vacuum leak somewhere?

Discharge nozzles loose/leaking?

Bowl vent plugged or damaged?

Too much fuel pressure?

Just a few quick ideas, without being there to see it in person!

Smokin Joe · 12-21-2003, 02:55 PM

Did this carb work on the car before you rebuilt it?
If it came from another car, did that one run?

I'd take it apart again if you don't know the carb and see if everything is what it's supposed to be. You'd be surprised what people do to modify Holley carbs. I bought one used years ago and had to change jets, springs, choke and about everything else. Found out later it was a carb off a gasser.

You probably have a stuck float as the first guess. The overflow is running the car instead of your idle circuit.

Hot Rod To Hell · 12-21-2003, 04:41 PM

Hey Hack... a vacuum leak would make it run lean...
I would give a good shot of carb cleaner or brake cleaner through the air bleeds (use the little red straw)and see what that does. As far as the float level, pull the sight plugs as soon as it dies and check it. If fuel comes gushing out, it's way too high... stuck float or something... if it doesn't, that's not your problem.

**Flat Ernie** · 12-21-2003, 05:22 PM

I'll second the air bleeds (little brass plugs w/small hole in top of carb facing up) - blast 'em with carb cleaner. I had one that was only partially plugged & it gave me fits for weeks until I found it. Not difficult to drop a piece of gasket scraping down the metering block or main body portion while cleaning the carb with it apart either!

To adjust floats, remember the screw on top just unlocks the adjustment - it's NOT the adjuster. The nut is the adjuster - clockwise lowers float level.

Now that you've monkeyed around with it & may not have a good idea where you're at with the float level to begin with, I'd pull the bowls & adjust the floats visually.

ith the bowl off, turn it upside-down & adjust the float level until the top of the float is level with the top (now bottom) of the bowl.

Set your idle screws 1.5-2 turns out & that should get you running.

This should get you running if everything is as it should be. If not, then something else is wrong & it needs to come apart again...

OldCarPilot · 12-22-2003, 01:04 PM

Some new observations. The secondary bowl keeps over filling with fuel. I have the needle set to where it should not be so high. I've even pretty much put the needle all the way down with should have not allowed ANY fuel to get in there and there was still fuel in there. I took the bowl off and visually checked the needle and float for good movement. Everything there looked good. Any reason the secondary bowl would get fuel from somewhere else?

Hot Rod To Hell · 12-22-2003, 01:42 PM

you may have a leaking float... It will fill up with fuel, and as such, won't "float".

flt-blk · 12-22-2003, 01:59 PM

check the float itself to make sure it hann't filled with fuel. I still have a float bouncing around the back of my truck had a pin hole and filled up, it never shut off the fuel supply.
TZ

skipperman · 12-22-2003, 03:17 PM

Also...make sure the "tang" on the float has not been bent outta shape........a little creative bending might fix it.....and shake it to be sure it has no fuel in it.....check the needle and seat REAL good !!

Jersey Skip

**Flat Ernie** · 12-22-2003, 04:55 PM

[ QUOTE ]
Any reason the secondary bowl would get fuel from somewhere else?

[/ QUOTE ]

No, as mentioned, you may have a sunk float. OR your needle/seat is screwed. If you've got the old one from before the rebuild, try it out. Also check the tab/tang on the float as mentioned.

Good Luck!

**BELLM** · 12-22-2003, 11:04 PM

Make sure your oil isn't contaminated with gas, quick way to ruin an emgine. Trust me. I've been fighting a out of the box new Demon, Changed oil twice in about 1 hr of running.

**Deyomatic** · 12-23-2003, 02:30 AM

One thing he hasn't mentioned is that the tube, not sure if it is a "bleed" or not, that sticks up out of the front of the choke horn is cracked down the side. The ONLY reason I mention this is because I've had fuel come pouring out of mine on a Holley before. Is it possible that some air to fuel pressure ratio is off because of this cracked tube?

OldCarPilot · 12-23-2003, 03:11 AM

I seem to have the secondary bowl under control. It is still getting more fuel than I think it should, but the level is good. It almost comes out of the site plug, but not quite. Long story short that seems to be what is not puring fuel in the carb. I can make it idle on its own if I allow the big vac port to suck air in. And its even better if I crack the secondaries. :-)
I don't think that tube is the prob. But who knows. I'll ask this though... The choke linkage has been taken off and the choke flapper has been wired open. Does the linkage being gone have anything to do with this?

12-20-2003, 05:18 PM	#1
OldCarPilot Senior Member Join Date: Apr 2003 Location: Kennesaw GA Posts: 1,266	Holley rebuild question Just rebuilt a Holly 600. This is my first rebuild on a carb so I'm sure I've done something wrong. What is happening is the carb seems like its DUMPING fuel in. Its all comming out the back of the car in a cloud of gas. I changed the power valve to see if that would help. Seemed like it helped for about 5 sec then it was running too rich again. I can screw the idle screws in all the way and still runs like that. Did I miss something obvious?

12-20-2003, 05:19 PM	#2
Fat Hack Old School HAMBer Join Date: Nov 2002 Location: Detroit Posts: 7,648	Re: Holley rebuild question Start with your float level adjustment, and also check to be sure that the needle and seat is not sticking.

12-20-2003, 05:23 PM	#3
Rocket88 Member Join Date: Jul 2001 Location: Abbotsford, B.C. Posts: 775	Re: Holley rebuild question Sounds like you've got some crap in the needle and seat.

12-20-2003, 11:52 PM	#4
Model A Vette Member Join Date: Mar 2002 Location: Central NJ, USA Posts: 789	Re: Holley rebuild question Did the engine backfire (even once) after you changed the power valve? If you did not add the checkvalve kit the power valve could be blown again. The kit is a ball and maybe a spring that is added to prevent the power valve from blowing every time the engine backfires. Years ago my Camaro had some downtime because I didn't know about the power valve blowing due to backfires.

12-21-2003, 12:07 AM	#5
Hot Rod To Hell Old School HAMBer Join Date: Aug 2003 Location: Flint MI Posts: 3,030	Re: Holley rebuild question If you have your idle speed set to high you will be running off of the MAIN circuit, not the idle circuit... the screws wont do anything if that's the case...

12-21-2003, 02:13 AM	#6
OldCarPilot Senior Member Join Date: Apr 2003 Location: Kennesaw GA Posts: 1,266	Re: Holley rebuild question No back fires, and the idle is not too high. I've done a few diffrent settings to play with it. I'll, now, play with the needle and see what I can find. Thanks all for the info!

12-21-2003, 01:04 PM	#7
FEDER Senior Member Join Date: Jan 2003 Location: Warm Beach, WA Posts: 1,071	Re: Holley rebuild question OCP look on the passenger side of the carb at the float bowls.You will see a flat head screw one for the front, one for the back. Remove the screws. Look for fuel to come out. If fuel is gushing out your float level is too high. On the top of the bowl is another screw and 5/8" jam nut. Loosen the jam turn the screw clockwise 2 full turns. Now you have lowered the float. Do this to the front and rear. Leave the side screws out -start the car Let it idle only. Now no fuel should be coming out either bowl. If so. Shut it off and lower the float some more-1 turn Restart and slowly raise the float,untill you see fuel just start to dribble out the side hole. tighten up the float screw and jam nut. Screw in the side screws.(sight plugs) and repeat on the rear bowl. WALAA you have just set yer float bowls so give it a try. FEDER

12-21-2003, 02:06 PM	#8
OldCarPilot Senior Member Join Date: Apr 2003 Location: Kennesaw GA Posts: 1,266	Re: Holley rebuild question Tried reseting the float. Biggest problem is I can't keep it idling long enough to set the float when its running. The car isn't "running rich" it is puffing fuel out the back in big grey clouds. Feels like a cylinder is not firing or something, but that is unlikely to be the case as the car was running fine with a (much newer) Holley 750 on it. I went though and checked all the plugs and cleaned them all up. Checked the needle and found no dirt or anything in there. Its like something is staying open spraying fuel down the carb. I can idle it long enough to let it run and look down the carb either. I have to keep my foot on the accelerator to keep it running. Bring the rpms up to about 1500, but it doesn't feel good. And then I just make a huge cloud of gassy smoke that I'm sure my neigbors love. I don't know what the deal with it is.

12-21-2003, 02:33 PM	#9
Fat Hack Old School HAMBer Join Date: Nov 2002 Location: Detroit Posts: 7,648	Re: Holley rebuild question Possible vacuum leak somewhere? Discharge nozzles loose/leaking? Bowl vent plugged or damaged? Too much fuel pressure? Just a few quick ideas, without being there to see it in person!

12-21-2003, 02:55 PM	#10
Smokin Joe Old School HAMBer Join Date: Mar 2002 Location: Idaho Falls, Idaho Posts: 3,545	Re: Holley rebuild question Did this carb work on the car before you rebuilt it? If it came from another car, did that one run? I'd take it apart again if you don't know the carb and see if everything is what it's supposed to be. You'd be surprised what people do to modify Holley carbs. I bought one used years ago and had to change jets, springs, choke and about everything else. Found out later it was a carb off a gasser. You probably have a stuck float as the first guess. The overflow is running the car instead of your idle circuit.

12-21-2003, 04:41 PM	#11
Hot Rod To Hell Old School HAMBer Join Date: Aug 2003 Location: Flint MI Posts: 3,030	Re: Holley rebuild question Hey Hack... a vacuum leak would make it run lean... I would give a good shot of carb cleaner or brake cleaner through the air bleeds (use the little red straw)and see what that does. As far as the float level, pull the sight plugs as soon as it dies and check it. If fuel comes gushing out, it's way too high... stuck float or something... if it doesn't, that's not your problem.

12-21-2003, 05:22 PM	#12
Flat Ernie Tech Editor Join Date: Jun 2002 Location: Redmere, Cambs Posts: 7,756	Re: Holley rebuild question I'll second the air bleeds (little brass plugs w/small hole in top of carb facing up) - blast 'em with carb cleaner. I had one that was only partially plugged & it gave me fits for weeks until I found it. Not difficult to drop a piece of gasket scraping down the metering block or main body portion while cleaning the carb with it apart either! To adjust floats, remember the screw on top just unlocks the adjustment - it's NOT the adjuster. The nut is the adjuster - clockwise lowers float level. Now that you've monkeyed around with it & may not have a good idea where you're at with the float level to begin with, I'd pull the bowls & adjust the floats visually. ith the bowl off, turn it upside-down & adjust the float level until the top of the float is level with the top (now bottom) of the bowl. Set your idle screws 1.5-2 turns out & that should get you running. This should get you running if everything is as it should be. If not, then something else is wrong & it needs to come apart again...

12-22-2003, 01:04 PM	#13
OldCarPilot Senior Member Join Date: Apr 2003 Location: Kennesaw GA Posts: 1,266	Re: Holley rebuild question Some new observations. The secondary bowl keeps over filling with fuel. I have the needle set to where it should not be so high. I've even pretty much put the needle all the way down with should have not allowed ANY fuel to get in there and there was still fuel in there. I took the bowl off and visually checked the needle and float for good movement. Everything there looked good. Any reason the secondary bowl would get fuel from somewhere else?

12-22-2003, 01:42 PM	#14
Hot Rod To Hell Old School HAMBer Join Date: Aug 2003 Location: Flint MI Posts: 3,030	Re: Holley rebuild question you may have a leaking float... It will fill up with fuel, and as such, won't "float".

12-22-2003, 01:59 PM	#15
flt-blk Old School HAMBer Join Date: Jun 2002 Location: Glen Ellyn, IL Posts: 3,644	Re: Holley rebuild question check the float itself to make sure it hann't filled with fuel. I still have a float bouncing around the back of my truck had a pin hole and filled up, it never shut off the fuel supply. TZ

12-22-2003, 03:17 PM	#16
skipperman Member Join Date: Dec 2002 Location: Atco,N.J.(Camden county) Posts: 880	Re: Holley rebuild question Also...make sure the "tang" on the float has not been bent outta shape........a little creative bending might fix it.....and shake it to be sure it has no fuel in it.....check the needle and seat REAL good !! Jersey Skip

12-22-2003, 04:55 PM	#17
Flat Ernie Tech Editor Join Date: Jun 2002 Location: Redmere, Cambs Posts: 7,756	Re: Holley rebuild question [ QUOTE ] Any reason the secondary bowl would get fuel from somewhere else? [/ QUOTE ] No, as mentioned, you may have a sunk float. OR your needle/seat is screwed. If you've got the old one from before the rebuild, try it out. Also check the tab/tang on the float as mentioned. Good Luck!

12-22-2003, 11:04 PM	#18
BELLM Alliance Member Join Date: Nov 2002 Location: Milano, Texas USA Posts: 2,383	Re: Holley rebuild question Make sure your oil isn't contaminated with gas, quick way to ruin an emgine. Trust me. I've been fighting a out of the box new Demon, Changed oil twice in about 1 hr of running.

12-23-2003, 02:30 AM	#19
Deyomatic Alliance Member Join Date: Apr 2002 Location: Wethersfield, CT Posts: 2,971	Re: Holley rebuild question One thing he hasn't mentioned is that the tube, not sure if it is a "bleed" or not, that sticks up out of the front of the choke horn is cracked down the side. The ONLY reason I mention this is because I've had fuel come pouring out of mine on a Holley before. Is it possible that some air to fuel pressure ratio is off because of this cracked tube?

12-23-2003, 03:11 AM	#20
OldCarPilot Senior Member Join Date: Apr 2003 Location: Kennesaw GA Posts: 1,266	Re: Holley rebuild question I seem to have the secondary bowl under control. It is still getting more fuel than I think it should, but the level is good. It almost comes out of the site plug, but not quite. Long story short that seems to be what is not puring fuel in the carb. I can make it idle on its own if I allow the big vac port to suck air in. And its even better if I crack the secondaries. :-) I don't think that tube is the prob. But who knows. I'll ask this though... The choke linkage has been taken off and the choke flapper has been wired open. Does the linkage being gone have anything to do with this?

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