perfect_circle

i just finished putting on my nikki carb, it is exactly the same as how it was when i took it off, and it was tuned, so i dont want to mess with a/f ratios. or my idle speed. ive got two problems. it cant hold an idle, so i thought it was a vacuum leak, so i remade the two gaskets between the carb and mani. but it did fix it.

and my second problem is when im try to warm it up, i will hold the throttle in place, and it will stay at a certain rpm, but then it will die off. but if i go up to above like 2500it wont. and when driving im having a really hard time accelerating, it wont go over a certain rpm in any gear, so i canm only 55-60 in 5th.

i think the second problem could be related to fuel pressure, because its the only thing thats been modified. but it only seems like it runs out of fuel for a second, because i drove it for a while after i got it up to speed, and it didnt seem like it was bogging or like starving for fuel. although it wasnt ver smooth either.

FYI, i did search, but ive come up with nothing, so i hope you guys can help me, and no, i didnt mess with my float levels.lol.

Kentetsu

How long was the carb off of the car? It almost sounds like your jet(s) are clogged. When that happened to me, I could accelerate if I did it slowly enough, and could even drive at highway speeds. But give it too much gas and it would start to die off.

When I'm warming up my car, it also will start to bog if I hold the rpms steady. I have to keep revving it a bit to keep it from doing this. I'm not sure why, but this has been the same with most carb'd cars that I've owned.

Verify that you still have leading ignition, and check your timing too. That's about all I can think of at the moment. Good luck.

perfect_circle

thanks, will do. and the jets may be clogeed, the carb was off for a while.

j9fd3s

iTrader: (3)

1st step in trouble shooting any carb is to make sure the ignition works and you have no vacuum leaks.

i rebuilt the carb on my 83 twice but that didnt fix the big chunk of air pump stuck in the acv... the jets dont meter fuel when theres no vacuum signal

perfect_circle

ok, well i checked for vacuum leaks, and i couldnt find any, and i checked the leading ignition,and its there. i played with the a/f's and idle speed a little, but made no headway.im thinking maybe if sprayed carb cleaner through the jets would that work, or no?? im up or anything. thanks for the help thus far.

edit: i know the timing is ok, cause it ran fine before, and i havent touched it.

j9fd3s

iTrader: (3)

if you spray a little carb cleaner into the carb and it picks up, its too lean. if you spray some in there and it dies, its too rich....

perfect_circle

can i use carb cleaner to check for a vacuum leak, i thought you could, and i sprayed it around the carb and got nothing, but when i sprayed it in, it didnt do anything either.

cdrad51

So tell me more about how was the fuel pressure modified?

perfect_circle

i have an aftermarket fuel pump with an mallory fpr.

i came up with the idea, that maybe my secondaries arent working properly. i know the stayed closed the whole time, becuase there was a little bit of fuel pooled, in them, and this could be causing my poor performance...right??

blwfly

iTrader: (4)

defintly lol do u have mech secondarys do the secondarys evan turn when u pull the linkage

perfect_circle

i thought so, but im going to go check again right now.

perfect_circle

yea, the secondaries are froze closed. does anyone know how to un-stick them without bending the linkage??

trochoid

iTrader: (6)

Use carb cleaner on the inside of the carb and the outside to clean off any gunk buildup, then P B Blaster to free up the linkage. Don't force the linkage and look for any binding that is preventing it from working. Download the carb manual from the archives and compare your linkage to the exploded diagrams.

cdrad51

And you have the pressure set at?

perfect_circle

its around 2- 2.5

i got the secondaries unstuck, and now when i start it, the revs jump to like 3k, and then slowly go down. like the throttle is stuck. i dont see any binding, the cable itself is free, and i dont understand how the sticky secondaries would effect it at all, seen as how the wont open until its under load.

cdrad51

Any reason for that fuel pressure setting? Stock fuel pump is 2.84 - 3.54 psi.

perfect_circle

i cant get it to change, i dont have the resistor in the return line, and im not using the return on my fpr. i adjust the screw, and it doesnt do anything. i think i may need a new filter.

i still cant get it to idle. no matter how much i turn it either way, it doesnt seem to effect the idle, but i can throttle and it will run at 800, not consistantly, but i dont think its a vacuum leak, then when i satb the throttle,it will slowly rise to like 3k, the even go down even slower. it seems like its getting to much fuel from the shot of the AP, cause the linkage comes closed right away.

cdrad51

Sticking float needles maybe?

perfect_circle

does anyone have any idea what would be causeing the rpms to stay elevated?

Kentetsu

Fuel leaking into the system somehow, or throttle linkage sticking, or vacuum leak. Do the butterflies close all the way when you are looking down into the carb? Actually, the primaries should be slightly open I think but the secondaries must be fully closed.

perfect_circle

i dont know about the fule leaking, but im pretty sure that the linkage is not sticking, and im also pretty sure that the secondaries are completely closed. it could be a vaccum leak, but i have checked several times, so im not sure, im going to take a nother look at it in the morning.

Kentetsu

Take a length of tubing (even a garden hose will work) and put one end to your ear. Use the other end to listen around the carb and intake. Works like a stethoscope, you'll hear everything. I could never get the carb spray method to work for me...