proper fuel pres. for a holly
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Why two regulator?
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bulb Feed in the bottom, out the two side's ? Pull the line's off the carb's and loosen the set nut on top of the regulator to back it off half way and see what happen's. At the carb don't exceed 9 psi. Start with 7.5 lbs and work from there.
I'm guessing you pull the float sight plug's ? Have you adjusted the needle and seat and are you sure your pump is moving the fuel ?
Sleeper CP
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4,288 Posts
I have only one regulator. The bowls are filled and adjusted to the bottom of the sight holes. I started,ran and timed it last night. Just cant figure out why I can't adjust it down. I thought I just had a bad regulator, but they both act the same. BTW is spinning the allen headed adj. on the regulator "in" supposed to make the pres go up or down? Oh I forgot to mention I have one of the outlet sides blocked off that wouldn't matter would it.
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1,417 Posts
Adjusting the screw "in" should raise the outlet pressure.
What port do you have blocked???
A picture is worth a thousand words!!
What port do you have blocked???
A picture is worth a thousand words!!
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10,102 Posts
One side wouldn't matter.
Back the adjuster/ Jam nut out to lower the pressure. That is why I said" back it out half way and see what happen's"
Sleeper CP
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5,291 Posts
here are the instructions here. you dont have a bypass reg do you?
http://www.holley.com/data/Products/Technical/199R7914-3.pdf
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5,790 Posts
If you truly can't get the fuel pressure down below 9, it's likely the internal bypass in the pump is stuck. I'd take the bottom part of the pump apart and make sure everything is clean and working right. When we ran Holley blue's in our lake boat, we struggled with the vanes freezing up from rust and the bypass sticking. Frikken pump gas had a lot of water in it.
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No it's not a bypass, but I'm starting to wish I did. When I spun it all the way in it did go up to 12 lbs. So I assumed I needed to back it out, you can tell from the pic it's pretty well all the way backed off? I dunno maybe my gauge is junk. I guess as long as the needle and seat is holding back the pres. it's all good? The regulator is a holly 12-803, it's not supposed to go past 9 lbs.
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5,790 Posts
+1 on the gauge...should have mentioned that first.
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3,142 Posts
I just installed the same reg on my boat, not trying to question your intelligence or logic but one of my buddies who was watching me install mine though the regulator should be installed before the fuel pump... so my q to you is... You do have the reg installed between the fuel pump and carb right? Not before the pump? I see your reg is connected to your filter so thats why i'm asking, my large filter like that is before my pump.
On that reg i was able to get my pressure down to 5lbs and i probably could have gone lower, my pump was pushing 8-9 lbs out of the box (my pumps a mallory)
On that reg i was able to get my pressure down to 5lbs and i probably could have gone lower, my pump was pushing 8-9 lbs out of the box (my pumps a mallory)
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4,288 Posts
Yeh the regulator and filter are after the pump. The pres gauge. is a cheap-o summitt liquid filled, I guess the only way I'll know is if I buy another? I could take the pump apart to see if that internal by pass is stuck but I don't know what I'm lookin for. The pump is brand new also. It doesn't go straight to 9 lbs it starts out at about six and then I can hear the pump changes sounds/tones then she goes up. This is with the key on and the motor off that shouldn't matter should it? My co-worker thought 9lbs was about right but he runs a deamon.??
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1,119 Posts
i would think 7lbs's might be good enough. i run a holley blue on a blower motor and that likes 7-9 lbs's. i also went with the next size bigger regulator as the one that comes with the holley wasn't worth a crap or not big enough can't remember wich. what size line runs from carb to regulator? -8?(should be at least -8 for that pump)if you run two regulators you actually further diminish your presure drop.now i'm no guru by any means and there are alot of peple here that know more than me. i'm just throwing this out there. it also strikes me as curious that the regulator is mounted low (elevation wise) mine is up high right by the carb. eachbowl is fed from one side of the regulator. regulator after the pump filter before. never had an issue. good luck. it'd be cool to see the solution posted here when you get it dialed. -Jas
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10,102 Posts
7 lbs is fine and the more power you have the better off you are having the Reg. mounted closer to the carb.
Sleeper CP
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4,288 Posts
Just for the record when I said 2 regulators, I meant that when I couldn't get the 1st one to get below 9lbs ,I bought another one.You can see em both in the pic one's on my rail kit. I'm curious to see what happens when brown arrives and I get the fittings to be able to shut my tanks off(only suck out of one at a time). A couple of times when I shut the key off it blew a bunch of air in my drivers side tank. I know that sounds strange.
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4,677 Posts
i have the same problems trying to set mine.i have to do it at the lake with the boat running.if i just turn key on i get all kinds of different readings,?????????
way it has done since day 1.i guess b/c it dead heads at the carb it wont read right unless it is runningbulb
way it has done since day 1.i guess b/c it dead heads at the carb it wont read right unless it is running
bulbI prefer to set fuel psi with engine running. #1 - engine is using fuel. #2 - full voltage to pump.
If you do it with engine not running, the fuel psi can be vastly different. Especially with dead headed systems, sometimes even with return systems.
Always verify psi's throught rpm and load range. Inconsistent fuel psi will cause inconsistent 'tunes.'
BTW: fuel psi can effect fuel float height and A/F ratios.
BTW#2: Liquid filled fuel psi gauges located where they can get hot will reduce the psi reading. I have seen the gauges read 3 psi less in a very hot application. This does not mean your fuel psi is actually lower, it is because the gauge is reading lower. Not blowing smoke here, I've had probably over 40-50 dealings with this and cost me some coin.
If you do it with engine not running, the fuel psi can be vastly different. Especially with dead headed systems, sometimes even with return systems.
Always verify psi's throught rpm and load range. Inconsistent fuel psi will cause inconsistent 'tunes.'
BTW: fuel psi can effect fuel float height and A/F ratios.
BTW#2: Liquid filled fuel psi gauges located where they can get hot will reduce the psi reading. I have seen the gauges read 3 psi less in a very hot application. This does not mean your fuel psi is actually lower, it is because the gauge is reading lower. Not blowing smoke here, I've had probably over 40-50 dealings with this and cost me some coin.
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