84 rx7 S 12A nikki carb emissions removed. 12a has perfect compression, electricals are fine.
I know I have a fuel clog/ resistance somewhere between the tank and pump. However, when i hooked up a dirtbike gas tank and gravity fed fuel into the carb, the car started and idled great but when I hit the pedal, she bogged down and hesitated. She is undriveable like this and I don't know what else could be wrong with this carb. I have rebuilt it and soaked/ cleaned several times. I have tuned it to idle correctly. The accelerator pump is squirting, but still crazy bad hesitation. I have been working on this running issue for about 2 months to no avail. I need help!

 

The carb needs the appropriate consistent fuel pressure (2-3 PSI) to operate, so just hooking up a gravity fed tank/petcock won't help. Clear out the clog in the tank and change your filter. Also, have a look at the screens around the banjo bolts on top of the carb. If junk made it that far down into the system then it would probably collect there.

 

Ok, I already plan on cleaning the tank and lines. There are no screens in there, are they required? Thanks for your reply!

 

just for S&G, check the air vent solenoid. I went for a test drive with mine unplugged, and it made my hesitation worse. I've been removing the un-needed bits off mine to help clear the hesitation up, and I think if I were to take that off and clean it, and clean the accelerator pump as mine is not working 100%.

 

I took the guts out of the carb vent solenoid and then screwed it back in as a plug. Was that a bad thing to do?

 

Depending on what parts you removed/plugged, yes; if it's now forced closed, you need it open when the engine's running to equalize bowl pressure to atmo.

 

I t is always open, I cut off the stopper bit inside and the shaft that moves it and just used the threaded part on the outside. I've found more threads with similar symptoms to me that say to flush the tank and blow out the lines. We will see if that solves my issues!

 

If you still have problems after you flush the tank and clear the lines, remove and clean the jets. There's a good chance they've gunked up if you've been running without the screens. I would run an extra screen type filter just before your carb. They usually have universal ones behind the counter at auto parts stores.

 

was it hesitating before you did that to the solenoid? i cleaned mine up today and it helped out a bit. i still have some hesitation, but not as much.

 

Any chance that you got the jets switched around during the rebuild? Secondary jets installed in the primary position would cause your symptoms...





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I think the jets may have got switched! 2 said 94 on them and 2 said 180: which ones are which? I thought the ones with smaller numbers on them would be for primary...

 

Smaller = primaries

 

The jets were in the right place... Still doing it. I'm going to pull the whole intake and check to be sure everything is sealed. A massive vacuum leak would do this, right? If this does not fix it, I'm going to be in the market for a new carb.

 

A vacuum leak would screw up your idle, and since you stated it idles correctly then I would rule that one out.