Carb. Question
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Senior User
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Carb. Question
Ok guys heres the deal, I have a 351w with about 375-385 HP Im guessing. I am running a Edelbrock Torker II intake with a Holley 750 double pumper on top. I have the carb's fuel mixture adjustment tuned all the way to lean and the carb is still running too rich at idle and low rpms. Is the jets too large for the small block 351w,Or do I have some other problems.I believe that the jet sizes are 65 on the primary side and 73 on the secondaries. Cam size is .512in-.512 ex 280 duration, compression is 10.5 to 1.
Thanks,
Randy
Thanks,
Randy
Mountain Pass
Joined: Jan 2001
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Carb. Question
Okay.. I had a Holley 750 on my 390, running perfect with 66/72 jets (pri/sec.)
65s are good in the primaries, Maybe try 64s or 62s.. 73s are way too rich in the secondaries. try taking it down to 68s or 70s....
How high do you wind your 351? jus wondrin...
My best advice is to just experiment around... I suspect you will find good mixture at around 64/70...
Good Luck!
J/.c
65s are good in the primaries, Maybe try 64s or 62s.. 73s are way too rich in the secondaries. try taking it down to 68s or 70s....
How high do you wind your 351? jus wondrin...
My best advice is to just experiment around... I suspect you will find good mixture at around 64/70...
Good Luck!
J/.c
Senior User
Joined: Nov 2000
Posts: 231
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Carb. Question
You can have a few possibilities causing your over-rich condition. (A)Power valve rupture/bad power valve gasket or gasket alignment. (B)Idle air bleeds blocked or partially blocked. (C)Due to the cam size, you may have to open up the throttle blades in order to get a decent rpm for idle, but what this also does is uncover the idle-tranfer circuits and allows main fuel system start-up causing an overly "rich" condition(burns your eyes). (D)Wrong or bad metering block gaskets. (E)Wrong idle adjusting needle screws. (F)Too high a float level. These are just a few possible culprits to your problem.
I hope this helps.
Todd
BB79RANCH
I hope this helps.
Todd
BB79RANCH
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Carb. Question
I failed to mention this is a brand new carb., so bad gaskets or power valves can probably be eliminated as the problem. The motor was just rebuilt and I have not had it out on the road yet because most of the interior is still torn out for restoration. As far as the RPM's, I'm guessing around 6000-6500 when I put on the strip later in the spring.
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From: Virginia
Carb. Question
If the camshaft is giving you a lousy idle with low vacuum,
your power valve might be coming on all the time, even though
it is new. You might have to change the valve to a lower number,
say a 3.5 or in that neighborhood. And, hate to pop edlebrock
lovers bubble, but a wild cam will require modification to the
needles and springs in those types of carbs too.
your power valve might be coming on all the time, even though
it is new. You might have to change the valve to a lower number,
say a 3.5 or in that neighborhood. And, hate to pop edlebrock
lovers bubble, but a wild cam will require modification to the
needles and springs in those types of carbs too.
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Posting Guru
Joined: Dec 2000
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From: Racine WI
Carb. Question
yea but atleast i wont have to change a power valve everytime the motor doesnt catch and push air back out the intake, or back fires thru the carb
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Posting Guru
Joined: Aug 2000
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From: PacNW
Carb. Question
>yea but atleast i wont have
>to change a power valve
>everytime the motor doesnt catch
>and push air back out
>the intake, or back fires
>thru the carb
FYI...new Holley's have built-in blow out protection for the power valves now. There are also kits you can buy to retrofit older carbs.
>to change a power valve
>everytime the motor doesnt catch
>and push air back out
>the intake, or back fires
>thru the carb
FYI...new Holley's have built-in blow out protection for the power valves now. There are also kits you can buy to retrofit older carbs.
New User
Joined: Nov 1999
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Carb. Question
I stopped my 750 double pumper from being rich all the time by adjusting the float levels down a bit. Air bleed screws out 1.5 turns. If it hiccuped, you might want to check the valve.
Now if I could just get rid of my stumble...
Now if I could just get rid of my stumble...
Posting Guru
Joined: Dec 2000
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From: Racine WI
Carb. Question
25 years later they devise a fix to a simple problem yeah i know they sell a kit its called a check valve , i still wouldnt run a toilet......opps holley, no flame intended i just dislike the brand just my opinion please dont get mad at me
Posting Guru
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From: PacNW
Carb. Question
No question Holleys are a PITA to tune, not great off-road and they've never been known for their mileage. They also have the biggest aftermarket support on the market so there ya go! It's a good thing that Edelbrock makes a lot of good stuff for the Carter (Edelbrock) so that at least we have a decent alternative.
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Carb. Question
Thanks guys for all the input ,I'll try some of the suggestions you all spoke of. Otto, I Know you love those Edelbrock carbs but if they are as good as you say they are, why don't you see them on NASCAR Engines. You know the big boys only use the best carb on the market and that would be a "Holley". 'Nuff said, case closed. :-)
Posting Guru
Joined: Dec 2000
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From: Racine WI
Carb. Question
Maybe its the same reason they rebuild their motors every friggin 2 or 3 hundred miles along with all the crap on the motor, if that spells street reliability you can keep it i need to go more than 2 or 3 hundred miles b4 i need to rebuild my carb, no thanks i will keep my edelbrock, lets try to remember your the one who cant get the ole holley to run decent i just bolted my edelbrock on set the idle hooked up the choke cable set the mixture screws and off i went i have no need for a screwdriver in the ashtray, so while your tuning ill be mudding good luck to you sir dont get mad at me, nuff said'
Posting Guru
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From: Racine WI
Carb. Question
i have a pile of holleys in the corner of my barn bout half a dozen not one of them ran decent its amazing how i ripped the nice double pumper of my 390 slapped a edelbrock on there ran 100% better actually idled smooth and didnt fall flat on its face when you stand on it, if you need some holley cores drop me a line i'll be glad to see them go to a holley freak