AFBCamaro

Hey guys ive been playing lately with every single carb known to man kind. Today I got a 700CFM double pumper Holley.

Is this damn thing supposed to squirt so much fuel from those four squirters holy damn. You can hears them swuusshshhhh.

It thought the DP is the only type of carb I have never used. This carb has been sitting for a while so I took it off the owner and bolted it on. (STUPID IMPATIENT ME)

Well I think the front needle are malfuntioning because i saw some fuel squirt right out of them. (I have not openeded the carb yet will do it tomorow to see what kind of jets etc it has).

The carb will idle at 1100rpms and seem fine and drop sligtly every 10 seconds or so in drive it drops to 400rpms. If i drop the throttle slowly to idle it will hold but if i wack the gas to full throttle and back out the engine will keep droping past idle rpm and die. So i have to slowly bring the RPMS down to idle in order to keep it running in drive.

At cruise it pops almost like its running out of fuel. When I floor it underload it revs without kick but it never goes through lean pop. Funny I dont know how anyone can go lean at WOT with those two pumps squirting the equivalent of a pint per pump.


Anyways im not trying to completely rebuild this thing just get a taste of what it can do. Do you guys thing a stuck or non working needle will cause these problems.

I will take the carb apart tomorow to check on the jets it has.....Will need more help soon, i will be back with a full report.

THANKS

EvilCartman

iTrader: (1)

If it's been sitting for a good while, things may be dried up and not sealing right. Also might be some junk in there. Then you need to tune it of course I'm quite happy with the 750 on my 305 Still get 20 mpg on the highway and much better throttle response than I did with the Holley S/A 670. Later this year though the 750 will be going on the new 355 Should be getting it to the machine shop end of the month or next month.

88Camaro350

How did you tame a 750cfm holley to run right on a mild 305? What jets? Your not running rich? My 670 SA ran pretty rich on my 305 out of the box. Stepped down a couple jets and tuned it and its good now. I can't imagine a 750 on a 305.

AFBCamaro

Stupid Double pumper.... I just opened it up and replaced the needle with some used ones i had laying around. I filled the bowls and they did not leak...GOOD GOOD... Cranked it and it would not catch. Then boooooom FIRE coming from carburetor. Lots of fire. Damn holleys and their stupid powervalves and leaks :-).

Well I cant do the easy cheap route its going to need a full rebuild. So Im taking it off and putting my old vaccum sec holley on there for now. I got to drive around town anyways I cant do it with small engine fires under my hood.

Man im bored im not rebuilding that holley anytime soon but here is what I found inside.

700CFM. 67 primaries- 71 secondaries -25 primary squirters - and 31 or 32 squireters out in the secondaries. It should have worked ok but somewhere its leaking or pluged up. If I get the carb from my friend for free then I will buy the rebuild kit for it.

Anyone running a 305 with a DP and an automatic tranny?

EvilCartman

iTrader: (1)

On my Speed Demon I stepped the jet sizes down to I think 75 in the front and 81 in the back. With the 670 S/A think it was around 65 in front and 71-72 in back.

EvilCartman

iTrader: (1)

Yeah, me lol

AFBCamaro

How does it run? Did it pickup anything. What does the difference feel like....

TALK TO ME

TALK TO ME

The 700 DP Has warped throttle blades another carburetor for parts. Thats why It was running so badly. I wish it was only tunning that I can live with and fix. Anyways anyone selling a DP carb for cheap :-)

Otherwise Carters here I come...again..

88Camaro350

I have like 64s in the front and 66s in the back. I have a pretty ****ty 350 right now tho. I figure when I get the lt4 cam, 1.6 rockers, and vortec heads im gonna have to step the jets up alot.

EvilCartman

iTrader: (1)

lol runs great and pulls pretty good It was an improvement over the 670 S/A holley for sure. On a hot humid day at the track and the first time out for me... the car ran a best of 15.21 @ 90.18 mph with a 2.19 60ft. Only made 4 runs and the last run was the best. I was thinking the next time out maybe take the 670 and swap at the track to see the difference. That's if I don't have my new engine in first. Around town driving is fine and can spin the rears with about half throttle from a stop. I hardly get into the secondaries at all even when passing on the highway.

Here's a dirty shot of it hehe... man I can't wait to drop in the new engine.