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PARKERRS
01-01-2007, 12:07 PM
I have an Edelbrock #1813 800 cfm AVS carb that is driving me crazy, hopefully someone can help me out. The carb was installed on a crate engine in Nov. '05 and ran fine during all dyno pulls. Engine was sat to the side while car was being completed. Car was completed in Nov. '06. The engine ran fine for a week or so only driven at light throttle or idleing. Then while tuning the transmission governer for proper shift points I engaged in several full throttle runs on the street to kick it in passing gear and check for full throttle shift points.
After about 6 times kicking it the carb started flooding at stop signs or lights stalling the engine and it would not idle for flooding.
Went home to shop, I have new tank, lines and pump, So I figured maybe trash in the tank or lines from manufacturing. I pulled the top off the carb and found no trash in bowls or needle and seats. At this point I thought maybe fuel pressure was too high from carter mech. pump, so I installed a regulator and gauge then set pressure to 5.5 lbs.. The carb still flooded at idle, so I again removed the top and this time lowered the floats below specified 7/16. This seemed to cure the problem, so I drove the car about 75 miles of stop and go traffic over the next 3 days. I parked it in my shop for about a week and then when I was going to get it out and polish it for a show that weekend it would not idle again, it was flooding.
I again removed the carb top and lowered the float level even more, and this cured the problem. I drove 80 miles to a show, then on the way home I stopped and filled the tank, suddenly it was flooding out at stoplights again.
When I returned home , once again I removed the carb top to find nothing amiss(aaarrrrgggghhhh!).So I removed the entire carb, checked the float levels, checked the floats( nothing inside when shook and dunked in pot of water- no bubbles), removed the primary boosters and blew out all passages with compressor and nozzle also checked them with .003 wire, and all were clear. I then blew out all passages in carb body, reassembled and reinstalled on engine. I started the engine and flooding was worse than ever, would not run below 1200 rpm. Fuel pressure was at 5.5, checked with 2 different gauges. When engine dies or is shut off you can both see and hear fuel being siphoned from bowls through the boosters and puddling in the primary venturi.
HELP! I don't know what else to check. Ive gone through checking all passages for blockage or restriction twice, checked the floats a half dozen times, set the levels lower than specified, fuel pressure is low enough for specs, choke is correct, I have also changed the needle and seats and checked them for binding or sticking, what am I missing? It seems to be more prevelant on the left bowl, when I remove the top the right bowl is full and the left is nearly empty, so I have gone back and checked everything on the left side of the carb again but no change.Edelbrock carbs aren't supposed to be this hard to deal with I thought, Holley's and Q-jets never presented problems this hard to solve.
Sorry to be long winded but I'm nearly ready to throw this carb in the dumpster out of shear anger and frustration.

Thanks, Tommy :help!:

Shaker455
01-01-2007, 12:57 PM
Tom,
I've delt with these carbs many times and it's best to follow your feelings and throw it in the dumspter!

I'm very sorry....they do not posess performance level of adjustability that I build into custom carbs.

It is critical to set the upper and lower float levels like it shows in the book that came with the carb and if you been only adjusting the lower level then more than likely you've lost your upper spec.

I'll dig out my book in the meantime and I'll try to guide you.

Another thing is the new gas is doing a number on the rubber needles causing them to swell and get distorted, and I see you replaced them as yours sat for an extended period.

What are you running this carb on and have to dialed in you idle mix screws in with a vacuum gauge?

Can you list you entire combo?

PARKERRS
01-01-2007, 03:52 PM
Upper float level is now at 1/2 instead of 7/16 as book states, the lower float level is set at 1 inch per book. Yes I have installed new needle and seats to no avail.. Carb is on a GMPP fast burn 385 backed by a 700R4. I know the 800 is large for this engine, the GM dealer replaced the 750 holley that came with the engine before dynoing it with an Edelbrock at my request. I had heard alot about them being a trouble free street carb, but I figured they would use a 650 and they figured using the 800 and leaning the jetting 8% was a better route.So much for trouble free! I leaned it additionally to 12% due to the fact that I used smaller primary headers than they did to dyno. I am using 1 5/8 primary try-y and they dynoed with 17/8 primary 4 into 1. The idle circuit has been set with a vacuum gauge for max vacuum.Also dyno runs were without air cleaner and I am using a 14x3 K&N.

Shaker455
01-01-2007, 07:04 PM
Tommy,
I got the feeling you went too far going 12% and how much vacuum are you pulling?

I would go exactly as the book specs ( 7/16" & 15/16") as I found that carb to be very picky about the float level and I hope you set the adjustment with the airhorn gasket in place.

Are you sure it's flooding and not starving for fuel?....when it floods out have you pulled a plug and is it wet or soot black?

What jets and metering rods do you have in there now?

I looked over the the 385's specs and I would say that carb is not fitted well to you combo....

If you like you can package it up and send it to me to check out...I'd be glad to take a look at it.

In the mean time may I suggest you take a look at your fuel filter....see if that didn't catch any stuff from your new system...maybe it's getting plugged up.
Jeff

PARKERRS
01-02-2007, 06:31 AM
Plugs are wet and soot black, I changed all of them once for fear of them being fuel fouled. Yes, I set the floats with the air horn gasket in place. I had lowered them to cure the problem the last time so when I changed the needles and seats I set them back at 7/16 upper and 15/16 on the lower, and that is when it will not run at all below about 1500 rpm. Yes I checked the filter, it is the Edelbrock inline with a small brass screen and it had 2 or 3 minute pieces of trash so I had purchased a spare in anticipation of this type thing and I replaced it then cleaned and stored the other. I'll have to check the rod and jet combo can't remember off the top of my head.I don't remember the vacuum reading either and since it will not idle right now I need to get it base line running to see. The carb started this when it was 8% lean and I leaned it to 12% while checking the floats, filter etc. and was going to run it a while and check the plugs but every time I've brought it in it is back to flooding so I know the plugs are black. I know it's flooding and not starving for fuel because fuel will be oozing from around the metering rod covers, and the exhaust will water your eyes from the rich condition. What carb do you suggest for this combo, hood clearance is limited with a '73 Camaro and flat hood with the GM high rise that came on this engine, I had to modify the drop base to clear the electric choke mech., The air cleaner isn't the contributing factor because it runs the same in the shop with it removed.

Shaker455
01-02-2007, 02:20 PM
Tommy,
I got your PM, give me a shout,

I know where your at with hood clearance as I also have a BBC 70' Carmaro.
Jeff

Shaker455
01-02-2007, 07:34 PM
Tommy,
Here's that post about Demon Carbs:

Demon's Demise - PY Online Forums

PARKERRS
01-08-2007, 05:03 AM
Finally got it straightened out, had to richen the jetting back up now that all of the flooding and internal problems are fixed. Thanks for your time and help shaker455, Once I have everything else dialed in I will probably be calling you.

koop be illin'
09-20-2012, 05:01 AM
I am having the exact same problem with 800 avs on Caddy 500. What was the internal problem causing the flooding. my problem comes and goes, otherwise identicle scenario