Carb problem.... I think.

[superj]

and no vacuum leaks right?

do you only have two mixture screws? sometimes four barrel carbs have four mixture screws. also, when you floor it from a stop (or anytime) does it kind of bog or stumble for a second and then pick up? from a stop does it almost die when you just floor it?

it kind of sounds like you have an accelerator pump issue also. pop the air cleaner off and look in the throat with the choke plates held open and pull the throttle arm to see if the two squirts of gas are squirting. if they are not, your accelerator pump is not working which will give you the dieing when try and speed up issue or take off from a stop

also, is your carb a vacuum secondary carb? since its mainly doing it from half gas and onwards, it could be your secondaries are not opening or opening to fast. you could have to large of jets on the secondaries also.

 

[Smizar]

Have you checked the vacuum advance diaphram?

 

[sweetpeet]

and no vacuum leaks right?

do you only have two mixture screws? sometimes four barrel carbs have four mixture screws. also, when you floor it from a stop (or anytime) does it kind of bog or stumble for a second and then pick up? from a stop does it almost die when you just floor it?

it kind of sounds like you have an accelerator pump issue also. pop the air cleaner off and look in the throat with the choke plates held open and pull the throttle arm to see if the two squirts of gas are squirting. if they are not, your accelerator pump is not working which will give you the dieing when try and speed up issue or take off from a stop

also, is your carb a vacuum secondary carb? since its mainly doing it from half gas and onwards, it could be your secondaries are not opening or opening to fast. you could have to large of jets on the secondaries also.

yes I have two mixture screws

when I floor it from a stop it goes immediately, no stumbeling or anything until i get to 4 rpm. without fail. it doesnt try to die until i reach 4 rpm and if i keep my foot down, it will completely. but if i come off within 3-5 sec then it falls down to .5-1 rpm and picks back up at that point where another step on the pedal will also kill it.

I couldent see down the throat but i recently took the top off the carb to install a offroad carb kit and I know that one of them works. but if the accelerator pump was broken then how much would it cost???

and i'm not sure what this means "also, is your carb a vacuum secondary carb? since its mainly doing it from half gas and onwards, it could be your secondaries are not opening or opening to fast. you could have to large of jets on the secondaries also." can you please explain?

 

[SteelHeadz]

Check the accelerator pump on the carburator. If it's the same as mine, it would have multiple holes on the plunger shaft protruding out on the top of the carburator. Make sure the rod is not bottoming out the plunger at half or 3/4 throttle, otherwise, it will stop pumping fuel out the venturis before you get to a wide open throttle. To fix this, you will need to pull the pin from the rod and leave the accelerator pump plunger disengaged. Pull the carburator throttle cable to the maximum open throttle and then see which hole the rod to the plunger can be most effective on the travel.

 

[sweetpeet]

today I did adjust the accellerator plunger. I moved it to the end hole and that seemed to work very well. hey SteelHeadz i dont want to be a pain in the azz but would you be able to get measurements of your throttle and your 2 mixture screws?

 

[superj]

if your timing is set right, your idle screw on the throttle arm should be only a half turn or a full turn past when it first touches.

the mixture screws should start at 1.5 - 2 turns in and adjust from that point. on four barrel carbs, i always found the setting usually ended up around 2.25 to 2.5 to be right

 

[Turbogus]

Sounds to me like it's starving for fuel on the high end, but I'm no expert.

 

[sweetpeet]

Sounds to me like it's starving for fuel on the high end, but I'm no expert.

What do you mean by "on the high end"?

 

[superj]

upper rpm

 

[Turbogus]

SweetPeet do you really have mixture screws on that Edelbrock Carter clone? Where are they?

 

[sweetpeet]

I really do have two mixture screws. How could it be starving at high rpm? Do you mean that my idling throttle is too low?

 

[superj]

no, he means like tis sounds like your not getting enough fuel in the higher rpms.

 

[sweetpeet]

But if I increase the fuel mixture I'll be too rich when im in the low rpms and idling. So it's gotta be something else. Right?

 

[superj]

the back two barrels on your carb are larger diameter then the front two. do they actuate using a linkage or using a vacuum cannister on the side of hte carb? you can't just open the linkage all the way and see if its working on a vacuum actuated 4 barrel because your not going to have enough load on the engine to create the pressure loss needed to open the back barrels. you can really only test the vacuum canister for leakage by sucking on the hose and seeing if it loses pressure and then sucking on the hose to the back barrels to see if the plates open. or using a vacuum gage. normally though, now that i think of it, when people wire the back plates to stay closed, it doesn't cause a bog or stumble like your getting so that might not be it. it might be that your back jets are not the proper size for your jeep

 

[superj]

did you already verify good fuel pressure in the upper rpms? your not sucking the bowl dry, are you?

did we already ask this

 

[sweetpeet]

did you already verify good fuel pressure in the upper rpms? your not sucking the bowl dry, are you?

did we already ask this

Yah I have been told to check it. But since I don't have the thing to test it, I have been trying to avoid having to do it. Lol

 

[sweetpeet]

So still having the same problem. Do you think that throwing the clutch would throw off my timing?

 

[superj]

Shouldn't have but check it since it's so easy to check

 

[sweetpeet]

I didn't check the timing but it seems to be running fine now and kinda drivable. However, I drive it and it tries to quit. Like the carburetor immediately steps down in the amount of fuel it is delivering. No matter how much gas I'm giving it, it will continue to slowly decrease fuel delivery.

So I'm not sure what's wrong with it. Has this happened to anyone? Anyone have any troubleshooting advice?

 

[sweetpeet]

Help??