Tired of crummy gas and leaking needle & seats

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MOPAROFFICIAL

MOPAROFFICIAL

Oogliboogli
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Every other month I change the needle n seat due to the o ring leaking or seat hardening, sick of it, my customers are sick of it. Last guy I did a motor for just blew his mufflers up stupidly continuing to drive the highway while it bucked and bog and missed......boom!! Both mufflers and the driveline went right after that....gawd damn astonishing .... he didn't know better, I do though and today I had to pull off the freeway, pull the needle n seat n flip the o ring and make it to work....till it did again on the way home....so I pulled the fuel hose off the secondary "i run a hose between each hard line in pri/sec" then stuck a 1/4 extension into the hose and reclamped it....then I took the sec throttle blade to down to closed and just added a turn the primary opening it a hair....then ran on the primaries home.

Gas sucks, rubber o rings suck, pump diaphragm material sucks....wtf
 
Check the fuel pressure. Get a regulator and adjust it to 5# and see if it helps. I ran into that issue a few weeks ago with a friends new engine. It ran great on the dyno with their electric pump and regulator. It was pig rich with a stock mechanical pump.
 
Rubber o-rings? Here is table for methane (methanol not listed but probably same) . Same as gas except last one, 1 is best 4 is not recommended :

Perfluoro-
elastomer 1

Viton
Extreme 1

Aflas
TFE/P 2

Viton
FKM 1

EPDM
P.C. 4

Buna-N
NBR 1

Silicone 4

Fluoro-
silicone 2
 
kiss said:
would adding marvel mystery oil to the gas help?
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Wouldn't hurt but probably won't help much. The OP is using the same gas as we all use. I have a Edelbrock carb on my 66 that I bought used and installed without overhauling it 10 years ago. Absolutely no problems. There is another underlying issue here.
 
FEP-Encapsulated Silicone O-Ring list Methanol but you still have the problem with the needle

methanol o-ring.jpg
 
Get rid of the Holley style carburetors for street cars.
No O-rings to leak!
No pump diaphragm to leak!
Fewer come-backs for you!
I hope your customer knows how to put out a fire.
 
There is something else going on here, unless the OP has an entire warehouse full of 1970 era carb gaskets and seals.
 
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toolmanmike said:
Wouldn't hurt but probably won't help much. The OP is using the same gas as we all use. I have a Edelbrock carb on my 66 that I bought used and installed without overhauling it 10 years ago. Absolutely no problems. There is another underlying issue here.
Click to expand...

Pretty much the same story here.
Going on 5 years with and Edelbrock and never had to change them once.
It was used when I got it and never rebuilt.
 
RustyRatRod said:
Just use non-ethanol gas.
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Not an option around here. I wish it was.

The guys at the small engine shop i worked at part time years back used to lament the ethanol crap b/c it just destroyed power equip.
They wanted to start selling non ethanol fuel and use the tag line "Gasoline like it used to was...."
 
sccachallenger said:
Get rid of the Holley style carburetors for street cars.
No O-rings to leak!
No pump diaphragm to leak!
Fewer come-backs for you!
I hope your customer knows how to put out a fire.
Click to expand...

SCCAChallenger,
What are you running in place of the Holley that alleviates these problems? I have an old OEM Carter from a 440 in a box, a Holley in pieces and the Demon 650 (Holley clone) that's on my car currently, none of these are exempt to leaking/damage from Ethanol.

Thanks for any input here!
 
ValiantOne said:
Not an option around here. I wish it was.

The guys at the small engine shop i worked at part time years back used to lament the ethanol crap b/c it just destroyed power equip.
They wanted to start selling non ethanol fuel and use the tag line "Gasoline like it used to was...."
Click to expand...
I see the OP's location is "Breakwater". Apparently they don't have non-ethanol gas there. I am surprised that even here in Iowa which is #1 in the nation for Ethanol production, we have non alcohol regular at most pumps.
 
MRGTX said:
SCCAChallenger,
What are you running in place of the Holley that alleviates these problems? I have an old OEM Carter from a 440 in a box, a Holley in pieces and the Demon 650 (Holley clone) that's on my car currently, none of these are exempt to leaking/damage from Ethanol.

Thanks for any input here!
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I more properly should have said it's the Holley with the externally adjustable float levels that have the O rings that fail.
My experience has been with Carter/Edelbrock carbs.
For a Carter needle and seat to leak and flood your engine, it's either loose (unlikely), has trash in it, or just worn out.
A Holley, with externally adjustable float levels can leak from wear, trash, or shrunken,broken O rings.
I drove my 340 home in stop and go traffic one day, with leaking O rings, not fun!
Had to keep it at about 2000 rpms just to try to keep it running.
if you run one of these Holleys on a street car, you'd be well advised to have a spare needle and seat and tools with you at all times.
Now when the Holley diaphragm starts to leak, it just drips on the manifold and you aren't stuck unless you have a fire!
But I'd carry an extra diaphragm too!
A Carter plunger style accelerator pump has a seal that will eventually shrink,or harden, and the pump won't work properly,but this doesn't ever cause an external leak.
Now track use, absolutely use the Holley, but peace of mind on a street car, Carter/Edelbrock all the way!
 
toolmanmike said:
Wouldn't hurt but probably won't help much. The OP is using the same gas as we all use. I have a Edelbrock carb on my 66 that I bought used and installed without overhauling it 10 years ago. Absolutely no problems. There is another underlying issue here.
Click to expand...
They have all brass needle and seats and a small gasket.
 
After experiencing the same exact issues, I dumped all the holleys and put thermo quads on all my drivers....no issues ever again for me.
 
ValiantOne said:
The guys at the small engine shop i worked at part time years back used to lament the ethanol crap b/c it just destroyed power equip.
Click to expand...
I have to get the gas jelly out of my lawnmower fuel bowl after sitting for a while. sucks.
 
You're not using just any old o rings from the hardware store, by chance?
 
Sta-Bil for gasohol works wonders. $12-$13 bottle treats 80 gallons. Cheap insurance if you ask me. Use it at every fill-up. My car, & lawn equipment sit all Winter and I've never had ethanol fuel problems in the Spring. (BTW non-ethanol gas cannot legally sold in CT.)
 
I rebuilt my 750DP in 1979. Then is spent the next 20 years in a bag. I bolted it onto my 367 in 1999. It has never been rebuilt since, and has been running 87E10 ever since.It's been apart lots of times,for tuning changes, but,the float valves may be original '70s.
It sits all winter, every winter. By spring of course the fuel is gone. I just fill it thru the vent-stacks, dribble a bit into the primaries and hit the key. I run it at a fast idle, just long enough to fill the secondaries, and then a bit of babysitting (no choke). Then it's business as usual.
Same fuel pump too,since 2004.

You guys must have different chit than we do,lol
 
67Dart273 said:
There is something else going on here, unless the OP has an entire warehouse full of 1970 era carb gaskets and seals.
Click to expand...

OK let's explore this...
I'm running the same 340 Kragen auto parts fuel pump for 15 yrs.
How many people run a stock 340 fuel pump and for how many years?
Sarcastically speaking the odds of said pump having internal malfunction that would cause some insane pressure spike seem fetched a bit...but het things happen....but let's add to the story. I cruise the freeway at 35- 4000 rpm, I stomp it and pass at upwards of 5500-6000 in 4th passing people like a rocket ship... I do this everyday now due to the trucks transmission being smoked....about 3 weeks now. Never had a problem before...and come to think of it, it did have fuel on the primary blades,more on the secondary but could have fountained out the bowl vent though...floats are set at half window.
410 Cid, real 10.1 comp , .575 solid roller , 4 spd, 750 speed demon 'more like 780cfm' 75/84 , msd 6a.

Hmmm. ...I'm either getting a psi spike, because it happens only sometimes and only after some hard wot...so i put an o ring on it and its fine.....for a day,then it acted like it was doing it again and got real dirty so I shut her down.....started it up 2 min later revs blow it out and clean it up and then I headed home and parked it in which it idled fine...but sputtered a tad shutting it off because I skipped octane boost last two gas stops.
 
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