Fuel Pressure

[oldbuck40]

well after one summer of repeatedly running out of fuel on top end i finaly installed a fuel pressure guage. i cant imagine why it was running out,the previous owner had it set for 1 pound. any ideas on what i should set it to.

[Taylorman]

Do you have an adjustable regulator? Holley says 5.5-6 psi. I dont have a regulator and see about with no problems.

[oldbuck40]

Without a bunch of info a ball park would be 3 to 6 pounds on a basic stock type deal. Some carbs/needle and seats can tolerate higher pressure with out blowing the seat and flooding your motor. Maybe start at 4 and go up until your troubles go away. I run 9 pounds on my blower motor.hey Dragboats whats up? im running a 850 speed demon at the moment and i cant find the dang instructions on it!

[Sanger Jet]

well after one summer of repeatedly running out of fuel on top end i finaly installed a fuel pressure guage. i cant imagine why it was running out,the previous owner had it set for 1 pound. any ideas on what i should set it to.
7LBS.

[oldbuck40]

ok loosen the nut then screw it in or out for more pressure?

[OMEGA_BUBBLE_JET]

first of all what kind of pump do you have? a regulator may not even be necessary. I have mine set at 5#'s if I remember correct. I used to have a fuel problem too, although turns out it wasn't the pump or the regulator or the carb. It was the 1/8" hose used for the pickups in the gas tanks :supp: 2 new gas tanks later with 1/2" tubes and no more problems. It is important to not confuse pressure with flow!
Omega

[oldbuck40]

first of all what kind of pump do you have? a regulator may not even be necessary. I have mine set at 5#'s if I remember correct. I used to have a fuel problem too, although turns out it wasn't the pump or the regulator or the carb. It was the 1/8" hose used for the pickups in the gas tanks :supp: 2 new gas tanks later with 1/2" tubes and no more problems. It is important to not confuse pressure with flow!
Omegahey omega! yea i got a holly mechanical 110gph with 3/8 line from INSIDE the tank all the way up to the pump. the book said it did need a regulator on it but i cant imagine,,well i can too! i remember when i bought the boat it didnt have a carb on it and i ask the guy where is the carb and what is it and he said its right in there on the bench,,its a 850 double pumper!!! i kinda got excited until i saw the quadrajet sittin there and he comes over and says yea i gotta get a kit from holly so i can fix her,,i just told him no thanks i'll buy a new one!!!

[OMEGA_BUBBLE_JET]

hey omega! yea i got a holly mechanical 110gph with 3/8 line from INSIDE the tank all the way up to the pump. the book said it did need a regulator on it but i cant imagine,,well i can too! i remember when i bought the boat it didnt have a carb on it and i ask the guy where is the carb and what is it and he said its right in there on the bench,,its a 850 double pumper!!! i kinda got excited until i saw the quadrajet sittin there and he comes over and says yea i gotta get a kit from holly so i can fix her,,i just told him no thanks i'll buy a new one!!! what is the pressure of the 110gph pump? If it was 9 psi or lower I would ditch the regulator. the holley regulators don't flow that well. Next big question is where are floats set? certainly you didn't just take it out of the box and bolt it on without setting the floats??????? If so you might want to check your float level and adjust it accordingly.
Omega

[oldbuck40]

what is the pressure of the 110gph pump? If it was 9 psi or lower I would ditch the regulator. the holley regulators don't flow that well. Next big question is where are floats set? certainly you didn't just take it out of the box and bolt it on without setting the floats??????? If so you might want to check your float level and adjust it accordingly.
Omegayes i did!! i took it right out of the box and bolted it on. filled it full of fuel and cranked it! float level was set at the top of the site glass on front and rear. Barry Grant has put it in writing it will run right out of the box! and the pump is set to 10 psi from factory and i think that is just too much!
besides a fire in a boat scares the hell out of me :2purples: im going to run it up around 6 and see what happens!!! i've got the sunshine and the warm weather all i need now is for the wind to lay some,,its blowing about 35 to 40 here right now.

[MudPumper]

I got the holly mechanical 110gph, I think it is pre set no need for a regulator, and holly 750dp. It runs consistintly at about 7lbs.

[MudPumper]

Yep, just double checked. No need for regulator, set to work between 7.5 and 9 psi

[sanger rat]

7LBS.
What he said. ;)

[Jake W2]

I have been told 7 lbs by quite a few.
Jake

[Old Guy]

Mine is set at 7#. However, I have a lot invested in my motor and I get all worried about not having enough fuel. This is what I use. At the far left is a pressure switch that is set at 6#. If the pressure drops to 6# or less, a small, very bright, red light comes on. It's on the instrument panel just left of the steering wheel. As the fuel filter gets clogged, the pressure drops and I know it right away. Works real good.
http://files.triton.net/old1/fuel_system.jpg

[steelcomp]

7 lbs is the norm for performance stuff. I'm curious about the float level...you said at the top of the sight glass??? If it were a Holley, which I imagine the bowls are basically the same, it should be at the bottom of the sight glass, or the hole. You set a holley by unscrewing the brass screw plug in the side of the bowl and with your fuel pump (if electric) or engine running at idle, the fuel should just spill out the bottom of the hole if you shake things around a little. Then I go another 1/4 turn down on the float adjustment. Maybe the BG's adjust to the top of the hole, but I've never heard of this. Float level is pretty important. If it's at the top of the sight window, how do you know it's not higher? :coffeycup

[NELSON#109]

ive always run 6 pounds, and ive always run big stuff... im kinda known for runnin hard for a long time, and ive never run outa fuel.... i had a deman carb, same as bg. and the floats adjusted to the bottom of the window, same as a holley...

[LVjetboy]

Pressure: Demon carbs are designed for 6-8 psi fuel pressure.
- I run dual 850's at 7.5 psi. I also installed a Livorsi Redline pressure gage on the dash with 5 psi set point and get no red light full throttle. So my pump, regulator, and line size are apparantly able to keep my engine happy to 6200 rpm.
Level: Next to the sight window on late model Demons are three marks (low - street, middle - street/strip, high - oval track)
- I run the Demons at half sight glass, the middle setting...not at the bottom as I ran with Holley. This setting was recommended by my engine builder and seems to work well.
jer

[OMEGA_BUBBLE_JET]

yes i did!! i took it right out of the box and bolted it on. filled it full of fuel and cranked it! float level was set at the top of the site glass on front and rear. Barry Grant has put it in writing it will run right out of the box! and the pump is set to 10 psi from factory and i think that is just too much!
besides a fire in a boat scares the hell out of me :2purples: im going to run it up around 6 and see what happens!!! i've got the sunshine and the warm weather all i need now is for the wind to lay some,,its blowing about 35 to 40 here right now.
well it does run! after all I have read I would loose the regulator all together. Believe it or not I ran my boat without a regulator for 2 years with a BLUE holley electric pump. I had a gauge on it and it was over 10psi and it never bypassed the needle/seat. I know....hard to believe. Others saw it too.
It is also important to mention that floats should be set with the boat in the water. If you do it on the trailer at least try to lower the tongue enough to get the boat to sit level. Otherwise you may set the rear float too low and not realize it.
Omega

[oldbuck40]

Pressure: Demon carbs are designed for 6-8 psi fuel pressure.
- I run dual 850's at 7.5 psi. I also installed a Livorsi Redline pressure gage on the dash with 5 psi set point and get no red light full throttle. So my pump, regulator, and line size are apparantly able to keep my engine happy to 6200 rpm.
Level: Next to the sight window on late model Demons are three marks (low - street, middle - street/strip, high - oval track)
- I run the Demons at half sight glass, the middle setting...not at the bottom as I ran with Holley. This setting was recommended by my engine builder and seems to work well.
jeri have it set on the high mark as LVjetboy say's above! as soon as the wind lays im going for a ride at 6lbs and see what happens!

[PLACECRAFT20]

I run the holley 130gph. No regulator. It sits at 7psi at idle and about 6.5 psi WFO. No problems with flooding an marine 850dp.

[oldbuck40]

I run the holley 130gph. No regulator. It sits at 7psi at idle and about 6.5 psi WFO. No problems with flooding an marine 850dp.hey PLACECRAFT20 do you happen to know a guy in longview by the name Rick Smith? he used to have an auto parts store on Gilmer road

[PC Rat]

It is also important to mention that floats should be set with the boat in the water. If you do it on the trailer at least try to lower the tongue enough to get the boat to sit level. Otherwise you may set the rear float too low and not realize it.
Omega
My boat doesn't sit anywhere near level on the water.
The manufacturer tells you how to adjust the floats by using the site glass or plugs as a reference. But aren't they trying to acheive a certain volume of fuel in the bowl? (as well as acheiving the level of fuel that keeps the jets covered vs. sloshing fuel out the vent.)
Brian

[oldbuck40]

after all said and done and adjusting the regulator in and out with no change i decided to take the regulator apart! found out the main spring on the adjusting screw was rusted almost in half and the diaphram was hard. so to see if i did have any pressure i bypassed the regulator and wha lah i have
14 almost 15 lbs!!! :2purples: so i have a new regulator on the way!!!
omega the reason i have so much is i run 2 pumps! 110 blue back at the Y by the fuel tanks and a 110 mechanical. the reason for this is simple i dont like cranking the hell out of it to get gas back up to the carb when i run out on 1 tank,its unnessasary and hard on the starter,battery and parts! just go back there and change tanks turn the key on let the pump run a second and your back on your way!!!

[Taylorman]

ok, next question. why not just the electric?

[oldbuck40]

ok, next question. why not just the electric?
ok what are you going to do when the electric puke's??? and your 10 or so miles from the boat ramp and your all by your self on the lake?

[jdf]

that's when i sit down and drink what beer is left,,

[oldbuck40]

that's when i sit down and drink what beer is left,,hahaha yea been there done that too!!!

[Taylorman]

Old buck, I thought about your post about having two fuel pumps yesterday at a time when i wish i had two pumps. It always happens to me that i have to crank the hell out of the engine to get gas to the carbs. I ran one tank out of gas yesterday and had to crank forever to get gas to the carbs from the other tank.
How did you hook up both pumps to feed the carbs? I want to connect a little cheap electric pump just to fill the carb when they are empty. Im thinking about tapping into my fuel supply coming of my filter and going into my mechanical pump. I have a Holley mechanical pump that has two outlets. The one outlet that is not being used is 1/8 npt. Im thinking about going into there from an electric. This will basically bypass the mechanical pump. Will this work?