lazy carb blues

[fryedaddy]

i bought an 850dp back in 1984 and i have put it on 3 different fe engines.i put it on my 433 5 years ago after it sat for a few years,it got corroded on the inside so i bought a new 850 and already got rid of the old one, problem is the old 850 was very crisp and quick revving and the new one seems lazy in comparison.im in the market for another carb that will perform like my old 850 did.  any recommendations.

[blykins]

Laziness or stumbles are generally lean conditions.   I think you can tune out whatever's amiss. 

[GerryP]

If it has replaceable air bleeds, or if not and you are inclined to tap the carb for them, changing the bleeds can help get the carb responding properly.  But instead of a new carburetor that may not work any better, ship out what you have to Pro Systems or DaVinci and let them tart it up for you.

[fryedaddy]

Laziness or stumbles are generally lean conditions.   I think you can tune out whatever's amiss.

its a good carb,i have it tuned in as good as i can.it just aint as crisp as the old one,i just thought maybe a quick fuel,aed or something similar might be better than a out of the box 850.im buying something,just looking for advice on my purchase

[351crules]

i personally think 850's are horrible carbs. not much venturi tapper and it's to big . they dont pull a good signal

[blykins]

If you're jonesing for a new carb, I'd do a custom Quickfuel Q-850. 

[fryedaddy]

If you're jonesing for a new carb, I'd do a custom Quickfuel Q-850.

which do you like,annular or the down leg boosters?

[wayne]

Find a 3310 -1 780 holley a lot of them on ebay now its one of the best holleys made, If you put a kit ln yourself and get a quick change klt for the secondarys and tune it to your liking you will be a happy camper  It was first made for a 396-425 hp chevy they got it rite,

[Falcon67]

i personally think 850's are horrible carbs. not much venturi tapper and it's to big . they dont pull a good signal

Agree - 750 or up to the "950".  Never met an 850 DP that I liked.  That's not saying you can't turn the lazy out.  But as above - large bore, not a lot of venturi action.

[351crules]

a holley 850 is different than a quick fuel.. quick fuel is actually smaller than holleys.. 1.40 venturi compared to a holley 1.562... lots of the non holley carbs are the 1.40 size.. 

[Falcon67]

That would sure help it be more responsive. 

[fryedaddy]

the reason i asked about annular vs downleg is that my engine has very little vac at idle and i heard annular boosters help that,and i go on a lot of short,5 mile or less runs with it,very rarely i go over 5 or 10 miles.i also heard annular boosters work the best with cooler engine temps.it hits 180 on the temp but im usually headed towards home buy this time

[Falcon67]

I have found that to be generally true.  The Holley (now Summit) 84xxx series carbs used what looked to be copies of the Ford 4100 style booters.  Large, profiled, annular. I used that carb on a mild 351 CID engine with a single plane intake and a fairly tight 2400 stall converter.  84011 Holley List number.  The car was very responsive with that carb.  Actually still have it in a box somewhere.