Here's the deal and what's going on. Twin turbo set from Mark Burton for my 350. It's on my 71 Skylark. Fuel system is Areomotive A1000, thru a couple of filters to Mallory 4309 adjustable bypass regulator supplying fuel to a Barry Grant 650 blow-thru. This is all runnign thru my gas tank using 3/8 line. Here's the problem. Turn on the key, hear the pump, and within a second the carb is blowing fuel thru all four boosters, I' m talking flowing. Spoke with Barry Grant tech idiots, told me to send it in and not to ##@! it or they would not warranty it. Sent it in, came back. Same old crap!!!!\ Any Ideas??? I'm thinking float level way to high??? But shouldn't these idiots have gone thru this carb when it was sent back?? When they returned the carb to me, all the invoice says is fuel pouring from boosters. That's it!!! No explanation of what they did or even if they fixed it!!! Talk about being frustrated!!!!! HELP PLEASE!
The first question I have is: What is your fuel pressure at the carb? It sounds like excessive fuel pressure overpowering the needle and seats.
Well, if that is accurate, then I would suspect the needle and seat settings and or problem. Those are the obvious things for your symptoms.
I also think that if you have three pounds fuel pressure at the carburator, the floates are way to high. I wonder why they did not have them set? At least close. Do you know how to lower them? If not. Remove the flat-screw from the side of the fuel bowl (on the driver's side). With a 5/8 inch boxed wrench on the set-screw loosen the large flat-screw on the top of the float. Have a helper turn the pump on. If gas flows out of the hole and it sounds like it will turn the nut clock-wise to lower the float until it just trickles out. * Clock-wise to rise the float. Then tighen the float screw and replace the fuel bowl sight plug. Repeat for the front and back. If it is as bad as you say, then I would lower them some (about one full turn)before you turn the pump on to keep from spilling that much gas.
I run 6psi for the base pressure on my Quickfuel. Only 3 things can cause this, too much pressure, bad inlet seat and valve, or float level too high. First thing to check is float level. My Quickfuel came set WAY to high. See the above post. Check the regulator. Block off the carb lines and see if you can back off the pressure to read below 1 psi. If you can't go that low your return line is too small. Demons are famous for coming out of the box with debris in them. Take the float bowls off and clean them and the inlet seats. I would have told the techs to go stuff themselves. Taking you carb apart does not void the warrenty! How the hell would you change jets!
Thanks guys. I'll start with the floats. Sailbird, your probably right about the return line most likely needs to be upgraded to 1/2" Onward.
What flat screw on Drivers side??? My float bowl windows are on the pass side? Anybody have a pic of this?? I put in a 1/2" rtn. Still gushing. The fuel is being supplied by 3/8" fuel line to 6an to the carb, would this be causing to much pressure??? HELP!!!
The type of questions you are asking prompts me to suggest that you buy a couple good reference manuals for tuning and services Holley carburetors. Reading one of these books should give you a strong understanding of what needs to be done and get you in the game. This is a Haynes Manual for Holleys is on Amazon: http://www.amazon.com/Holley-Carbur...=sr_1_3?s=books&ie=UTF8&qid=1283217991&sr=1-3 I have a book that I have had for years and always liked it. However, this book is filled with more advanced modifications and would be better after you have some more experience: Super Tuning And Modifying Holley Carburetors Performance, Street, And Off-Road Applications By Dave Emanual
If you had major fuel flowing down the intake like that, turn your motor over by hand a couple of times to make sure you don't hydrolock a cylinder. Change your oil!!!!!!!!!!!
Heres the deal, there is not flat screw on the drivers side of the BG blow thru carb. There is nothing, it is solid. On the pass side there is sight windows. Sailbrd thanks for the link. Hopefully I can figure it out. I can tune a Q-jet to a T, but this carb is tottally different to what I am used to. Thanks for the suggestions> J
My last older Holley had one, but as like everything else when one person does it and it works everyone does it. My new Quick Fuel does not (also Holley design). set the floats the same way other wise. Now you just do not have fuel running out onto your intake. The general rule on return line are that it needs to be the same size as the feed line or one size bigger. To see if it needs to be bigger do what sailbird said about the regulator.
I had the exact same problem. New A1000 fuel pump through new braided fuel lines to Aeromotive regulator to BG 650 blow thru carb. I was running 6 and up to 8 psi while I was tuning. It ran great for two days then flooded every where and the car died. Then the starter motor died trying to restart the damn thing. I removed the BG gblow thru ccarb and put the old Rochester back on, It worked fine at 6 psi regulated fuel pressure. I then pulled the BG 650 blows off and they were full of internal hose rubber from the fuel lines which I imagine came from the new connections as the suction and dischage filters are way back in the boot of the car. Cleaned the carb up but I didn't put it back on the intake, I'll do that when Mark sends the new X factor manifiold and turbo gear. Then I'll wet test it up to 12 psi before installing it. My new fuel filters were also plugged up I guess from the return line connections going back to the gas tank. See if taking the carb bowls off helps that's whre I found all the junk.:beers2:
We are all dumb small pack animals. Junk in the float valves will flood them everytime and should be the first thing to check.
Hey Byron, Sorry for the delayed response, I was in the hospital for a while due to having neck surgery. I don't have any engine pics but could get some if U want. Looks like Jay3000, just not as pretty.
