Thread: carb trouble

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Holley 1850 on a 302.
Runs pretty good, just rebuilt it and had to do alotta work and parts swapping to get everything going with it.

Few ???'s as I'm new to carbs:
Idle screws do nothing.... I set the floats correctly, transfer slot has less then 20thou showing. What else could cause it?
and it idles like a drag car (which I don't mind, but it seems odd).
Exhaust is kinda smokey

I *would* say the engine was wornout, but with the old 2v intake and 2150 it ran pretty smooth.


any ideas are appreciated.
Drew

Did you check the clearance between the accelerator pump rod ? It must be set at between .015-.020, I usually set mine at .017 . It is a pain to set, you have to do it with the motor NOT running. Hold the throttle at wide open, then have someone push down on the rod and put a feeler gauge between the bottom of the rod and the pump. Then adjust the nut with the spring accordingly to get the proper clearance.

too rich maybe?

pull one of your plugs. it should tell you alot about what is going on. sounds like your carb is filling up and you are not burning your fuel properly.

Originally Posted by jyardgirl

pull one of your plugs. it should tell you alot about what is going on. sounds like your carb is filling up and you are not burning your fuel properly.

I'm impressed, you go girl.

thank you. you are a sweetie

roger roger....
Accelerator pump is set properly.
Will check over fueling, and I'll report back.
where is a good place to start with jets? I've got 68s in there now.

Have you checked the power valve, even new ones tend to fail and the idle air bleed ports at the base of the front air horn might be plugged.

air bleeds 'should' be good as everything was soaked/blown out when I rebuilt it.
I may plug the power valve temporarily to rule that out.

will take the primary bowl out tommorow and mess around with it a bit.

thanks,
Drew

I've got a 650DP on a 289 and there are 62 jets in the primary and it's still a little rich.

ok so progress as of now....
changed jets to 64 (the smallest I have on hand)
no joy
changed power valve (again)
no joy
Plugs show overfueling and idle screws still have no effect... so where is the extra fuel leaking from?
Looking in the carb while engine is running doesn't show anything leaking.
Manifold vacuum is 15.5inches, slowly drifts to 16 than back. Acceleration and decel effect vacuum as it should, so I'd say no air leaks.

I need to find another good carb to use just to make sure I'm even looking in the right direction but my neighbor is a chevy guy (only has Quadrajets).

any other suggestions?
Last day home, ship out @ 4am, so I'll mess with this for a few more hours than get back to it in 4-5weeks.

thanks
Drew

For example.....

http://s68.photobucket.com/albums/i6...p.mp4&newest=1

whats your fuel pressure?

DeepRoots

Have you checked the secondary stop screw to make sure they
close all the way?

And I seem to remember some OE replacement Holley carbs had a
lean idle circuit and the idle screws turned out to lean and in to richen.

Might be worth lookn at.

no secondary stop screw present. Visually inspecting it on and off the vehicle shows that it is indeed closed.
These are standard idle screws, either direction (even all the way in) has no effect tho.

I have no way to check fuel pressure while running (at this time) I did however pull the fuel line where it enters into the carb inlet, hooked a pressure gauge to it and fired up the engine.
It ran for 20 seconds with the fuel in the bowls just as rough as normal. The fuel pressure was high at 8.5 psi.
Dunno if this line of thinking is correct or not, but my thought on the high fuel pressure is this: 1. First the engine still ran the same way, even while not using the lift pump. 2. The fuel level in the bowls (check with engine running and sight plug open) remained at the same level, so it isn't bypassing/overpowering the needle valve.

still puzzled....
and thanks for all of your help,
Drew