Carb Help

[chevymaniactn08]

i have a 305 with a weiand intake, hooker headers, msd streetfire distributor, and a 650-750 holley carb....my car cranks fine but wont stay runnin if i take my foot off the gas...it runs fine when i rev up the engine..and when i take my foot off the gas its idles down and spit fire out of the carb....i thought i was gettin a good deal on the whole car...i still think i am....the guy sold it to me cuz he thought it was a tapping lifter that he heard while the car was running...come to find out it was a loose rocker arm....i havent checked the timing cuz i dont have a timing light....i also chancged the plugs and they nwere soaked with gas...too much gas maybe?ne help would b appreciated

[silicon212]

Sounds like a timing issue to me. Have a friend keep it revved up while you turn the distributor to see if you can get it to run better. You can 'get by' without a timing light, temporarily, by finding out where it starts knocking and then backing it off a couple degrees (barely turning the cap). Turning the distributor clockwise retards the timing and counterclockwise advances.

[chevymaniactn08]

thanks alot silicon...im going to try that early in the morning...thanks for the quick reply...ill let u know how it goes.

[chevymaniactn08]

i left out one thing.....i was turning the idle mixture screws on both side of the carb and when i did.....no change in how it was running

[463]

you could have a good look at the vac lines ,make sure that there on and not cracked/leaking. it maybe a timing issue along with a holley carb problem.

[463]

one more thing pull the dipstick and smell it. if you have a raw gas smell it will more than likely be that the floats are set to high or leaking on the seats causeing fuel to dump in uncontrolled into the engine causing the back fire & wet plugs and the worst gas in the oil. ( fix the carb & change the oil and filter) thats from the "been there done" that file.

[chevymaniactn08]

ok cool...fixiing the carb...wut exactly do i need to do to acheive this...

[463]

650-750 holley carb rebuild book for starters. this is best left to a builder/ good mechanic thats got some holley experience. the holley carbs are for the most part straight forward. here is a link:http://www.chevyhiperformance.com/ho...798/index.html http://www.chevyhiperformance.com/ho...798/index.html

[chevymaniactn08]

wow guys......i jus may b gettin too much gas....i toook the spark plugs out and they were soaked with gas....i mean soaked.....also....i took off the valve covers.....my oil was milky lookin....but not totally white....i have a pic i took but i have to find my usb cable so i can post the pics off the inside valve cover...

[chevymaniactn08]

i jus found out that the carb is a 600 cfm holley....i didnt think a 600 cfm carb will give a 305 too much gas...is this possible?

[463]

this is possible. the carb is like a tank on a toilet. when the gas is pumped into the carb via the pump the float in the bowl will rise with the gas and when it is at the set hight/point the needle-and-seat assembly will stop the gas. if this float is set to high the extra gas floods over the top and floods the engine/washes the cyd walls passed the rings and into the oil pan. the gas will not stop if the needle-and-seat assembly is damaged.

[chevymaniactn08]

and the needle and seat is wut shoots da gas down into the carb right?

[G.A.S.]

do you think you can set the floats with some direction?

[chevymaniactn08]

of course....im a fast learner....wut about the milky lookin oil....is dat from the gas too?

[G.A.S.]

ok, :
Air cleaner off.
On the sides of the flost boals, there is a screw head that is about half to /3/4" of the way up the boal. This screw is 1/4" long and has a gasket/O-seal on it. It is easy to drop it is so short.
......these need to be removed.
On the top of the carb there is another screw and it has a nut under it. the location is on the top front float boal and the rear is on the top rear of the boal.
the ones on the sides are for the (eye) sight level.
the ones on top set the floats.
You need a good flat screwdriver and a 5/8" box end wrench.
Put a rag under where the eye holes are. this will catch any spilt gas.
Adjusting the floats is easy.
Loosen the screw head on top 1/8 of a turn, not much more or gas will spit out when running and making adjustments.
You need to hold that screw still and turn the nut. Counter clockwise will lower the float and visa versa.
You should set the floats so the gas just sits at the bottom of the (eye) holes. Some like it to trickel out but if you see the gas is right at the bottom of that hole, Just sitting there, your fine.
If this is a doubble pumper, the front boal will use gas as it idels so setting it is easyer.
On the rear you might need to manually pump the plunger to lower the level in the boal or you might go to low.

If this is parcially your issue and the high low adjustments are out.
dont start the car, pull a coil wire and roll it over so the gas will pump into the boal. this way you can set it easyer without fighting to keep it running.
With screw in boal, roll over engine, remove screw. If gas comes out, lower float. Now do the back one.
I hope this helps. I have to run right now but will be back in two and 2.