Fired up my motor yesterday and got it running good and timed. The problem is when I shut the motor off. After a about a minute, the primary carb starts to leak from the tiny holes on either side of the carb in the base plate. See the picture. I also noticed that gas continues to slowly come out of the jets even after the the motor is shut of. Not a lot, just seeps. Anyone have any idea?
too much fuel pressure. Gas is probably getting by your needle and seat. Some of the Carter experts will probably log in with a good psi range. My webers leak all over the place above 3psi
Install a regulator with a return line back to the tank. Set fuel pressure to 3.5-4 PSI. I am ***uming the floats are set correctly and the needle and seats are sealing.
Thanks for the advice! I have a Holley 12-804 fuel pressure regulator. It has 1 in port and 2 out ports...Can I run one of the out ports to the carbs and the other to the fuel tank as a return?
On my set-up, which is the same as yours, I run the right port to the carbs and the left one I've got a pressure gauge. You can use the port where I have the gauge and run a return line, although I've never needed one. I set the pressure at 4 p.s.i.
Mine is set up similar to oldschool66's, set at 5PSI. I've run several multi-carb set ups & never used a return line.
Great thanks guys! Ok... So next is vacuum. I currently have the primary carb vacuum plugged. Do I need to run a line to it from the intake?
I ran manifold vacuum on my 3x2 setup. Seems there is a lot of opinions on this subject. The 348 tripower ran vacuum from a hollow stud that was also used as a carb base stud on one of the carbs FWIW.
Just so I understand... If my mechanical fuel pump is 8-10 psi and I use a pressure reg after the pump, won't the pressure be so great that it will need a return line?
Don't think so...I am using the original valve covers that have the oil fill cap breather hole in one of them and a breather hole in the other. I was planning on running breather caps like the covers are permitted for. The only vacuum I am using at the moment off of the intake, goes directly to the transmission. No power booster for the brakes. Bare w/ me guys... This is my first duel carb set up.
If you like to tinker, you picked a good set up. The home brew tripower will require some attention to get right. One thing is for sure, its very gratifying when its dialed in. If you want to get the most out of driving light footed on a two barrel, you will need to also dial in your ignition with a good mech curve and a matched vacuum advance. There is some very good info resources on the net if you search it out. Where did your carbs come from? Are they three primary carbs or is the front and rear set up for true tripower?
Great advice, thanks! Both outside carbs are dumpers. I am running a Pertronix electronic distributor w/ mechanical advance. Do you have an thoughts on vacuum for the carbs?
I run trips on mine with no regulator, I was told that Rochesters are OK with 8 psi.Strombergs need a regulator. when you say that its leaking past the "jets" do you mean the accelelater nozzles? Check for the little check ball in the port where the accel pump sits( should be in the bottom) & make sure you secondary ****erflies are closed tight. Take your ****** vacuum right off the manifold, not off the carb.And lastly check your float heights. JimV
Here is a link to an article that does a very good job on explaining ignition timing and vacuum advance. Probably the least understood area of tuning an engine. http://www.lbfun.com/warehouse/tech_info/timing & vacuum advance/Vaacuum_Advance_Specs.pdf
i had the same problem. messed with the float, installed the edelbrock version of your regulator and gauge. set that thing to 3 lbs, no return. worked like a charm.
So no return at all...Not even off of the fuel pump? I have no return out of my mechanical pump? Do you have a return off your pump?
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