Stumbles/Stalls out whenever you stomp on it.

[Anonymous]

I've got a 250 w/ duraspark, clifford headers, c4, a msd, and a carter rbs. Whenever you stomp on the gas, in park, in gear, hot, cold, whatever, it stumbles really bad. My brother says the accelerator pump on the carb has probably gone but it is new. I'm also not sure if the fuel mixture is any good. I just adjusted it till it idle its highest and said "thats good enough." Any ideas whats wrong?

 

[BIGREDRASA]

Did you set the idle in park or drive? Are both advances on the dizzy working? Have you tried advancing the timing a couple of degrees at a time, until it pings under part throttle, then backing off?

 

[Anonymous]

I set it in park. The vacum advance is connected to the port on the carburetor that says DIS, I'd assume that means distributor. I think I may have advanced the distributor, but I thought I did it so it doesn't ping under full throttle up hill, so it wouldn't ping at all. I can't remember how we did it. Would that make a difference though? If I stomp on the gas even when I"m moving you hear it stutter.

 

[BIGREDRASA]

If you're pretty sure the carb's OK, then it's a pretty safe bet you're not getting enough advance. Make sure initial advance is set with the vacuum advance disconnected. I advance it a couple of degrees, then go floor the gas from standstill in D2, for a second gear start. If it doesn't ping, I advance a couple more degreees. If it pings, back off one. Works for me.

 

[Anonymous]

hey dude...u got the same problem as me...except i think the problem is my carb....i had a EGR vacuum leak which made it worse and its sorta slightly fixed with the leak fixed..timing is set to optimum for the best running and least dead spot...in park it idles a little rough, but purrs real smooth in drive....when i get rich enough again i think i will try a new carb...mine is a carter YFA and the lower part of the carb is slightly off from the middle part..i tried to grind it and that also helped somewhat but its too far off to get nice and smooth..if a new carb doesnt help, then i will need to look elsewhere....I also have a carter RBS which really didnt do me a whole lota good....i rebuilt it and the rubber part on the accelerator pump came off a while later..before i rebuilt it i had used up half a tank in about 10 miles...dont know what was up with that but i decided to leave the carb alone...but i cant see your carb being the problem since its new, but having the highest possible timing sure helps reduce the dead spot...but doesnt eliminate it..it reallly sucks

 

[Anonymous]

mine does that when cold...I think mine is becaus emy choke is virtualy off and I have a low idle on purpose...to save gas

Maybe your float is stuck...

My feel is its the carb, not timming on your car...

but remember...I am an ametuer...not even a shade tree mechanic

anybody remember that show?

 

[gtm1086]

It sounds like a acellerator pump issue to me. I don't have that carb. So I can't tell you if you can get a larger accellerator pump nozzlle. Most Holley's have replaceable nozzles. if you can't get a larger nozzle get a set of number drills and start enlarging the nozzle a couple of thousands go out and try it if it seems better enlarge it some more. Of course you need to make sure you have no vacuum leaks first and that everything else is set up properly.

 

[Anonymous]

nah...just buy a new pony carb

i wanna do that. I heard it takes care of a lot of problems

 

[Anonymous]

for a 250 would a carter YF carb be better than a YFA? the cost is only 20 dollars differance

 

[Anonymous]

If you have the RBS carb, it probably is the accl. pump. I have never been able to get the pump on any RBS i have had to last more that 1 week. Right now, Its not much of a problem for me, as I only get hesitation off idle, but I think it has somting to do with the design of the carb.