Eastman51

I have a 1983 GS. Ever since I got my car 2 years ago I've dealt with carb issues off and on, but for a long while everything was good. A few occasional random floodings when coming off the highway, but nothing I couldn't solve easily and without impeding traffic.
Idle speed has always been difficult to reign in, but was generally "good enough." Fuel filter was replaced within the last year and a half, tank was cleaned prior to purchasing the car. I have added a secondary filter before the carb.

So, early this year my pilot bearing disintegrated and I pulled the motor to overhaul a bunch of gaskets and change the clutch/pilot bearing. I pulled the carb off the intake and it sat on the bench in the garage for about a month and a half or so. I had intended to rebuild it, but never got around to it by the time the motor went back in.

I should note that I did modify the rats nest before the motor went back in. I'm bypassing the vac advance solenoids, deleted ACV, and one other solenoid I can't remember off the top of my head. I still have the relief solenoid, shutter valve, and AC. No rats nest, just vac hoses running around. Vac advance is hooked up. I ran my hoses in accordance with the emissions diagrams in my 1983 FSM and the diagram found on the hood of my car; obviously blocking off and neglecting to route hoses for what I have deleted. Nothing should be out of place.

After the motor went back in, I replaced the plugs and it was running fine. I ran into an issue with a low idle and occasional stalling at night (all lights on/loaded alternator); my idle speed screw was doing nothing. So I decided its finally time for the carb rebuild.

Stripped it down to the throttle body, cleaned it, put it back together. Only thing I didn't remove were the primary jets because I didn't have a screw driver that would fit through hole and be large enough to unscrew them. Followed the carb manual pretty much perfect.
Motor flooded to high hell when I put the carb back on. Took it back apart and realized that I had installed the needles wrong, the little spring things were keeping the floats from closing up the needles. Fixed that and it started up fine, but with effort since it had been flooded really bad.

Feels fantastic under 4k rpm, way better than ever. Good response, power, etc. But above 4k rpm it feels lifeless and slow; I suspect something is wrong with the secondaries. I'm fairly certain they aren't opening, since the blades move perfectly fine when I actuate it by hand with the engine off. I have yet to see if rpm increases when actuating them by hand with it running. I know the jets absolutely 100% move fuel from when it was flooding due to the float issue. Accelerator pump also squirts fuel. Secondaries were definitely working before the rebuild. I didn't even take the diaphragm apart, just replaced it's gasket.

This isn't my only issue, however. Shifting from 2nd to 3rd results in a huge bog randomly. And when the rpm drops to idle after having driven around, it drops dangerously close to stalling and then stutters its way slowly up to 900 rpm where it then levels out nice and smooth. Then if it idles for a minute, when I blip the throttle (even as little as to set off casually from a stop) it sputters and then takes off like normal. The idle speed screw now functions, apparently it somehow got threaded out too far and wouldn't contact the throttle stop. I don't seem to have any vacuum leaks.

I couldn't find anything helpful on how to proceed here or in my FSM, so here I am.
Would love to fix this without taking the carb off/apart again, but if its necessary I will do so. If you need pictures, just let me know.
Any ideas??

Rx7bgs366

Maybe a vacuum leak

Eastman51

I'm pretty certain it doesn't have a leak, but it wouldn't hurt to check it over since the carb has been stripped down since I last tested it.
I'll also see if manually opening the secondaries by hand does anything.

Eastman51

Well. I didn't even get so far as to check for vacuum leaks.

The carb decided to start flooding REALLY REALLY bad. Had to unplug the fuel pump and deflood to get it started again, and then even had to stop a second time on the way home from a short drive to deflood a second time. Carb 100% has to come back apart. Ironically, I think my secondaries may not be actuating due to throttle cable adjustment, maybe. Can't check now since it barely runs in its current state.

mazdaverx713b

iTrader: (91)

First thing if your carb is filling with gas....your floats are sticking or stuck. This is allowing gas to flood the bowls as the needles are not seating in the seats.

Next, I ran into the secondaries not operating issue once, years back after rebuilding a carb. The lower gasket between the throttle plate and the main body was installed upside down and was cutting off the vacuum port for the secondaries. I did this by mistake. I flipped the gasket over and all was well after that.

Eastman51

If its not my throttle cable, it probably is that gasket. I was sure I made sure no passages were blocked, but if I have to take it apart again to check the floats it wouldn't hurt to check.

The first teardown I used the included new seats and needles in the Hygrade kit, but that was so bad it wasn't even worth trying to start. Tore the airhorn back off and swapped back to the old seats and needles, and it was still flooding. Realized I had installed the needles wrong (the little spring things were facing the wrong way and not allowing the floats to close all the way. It ran ok, minus the issues mentioned in my original post, but ofc last night decided to act up again.
I have no idea what could be wrong....

raven12aFB

The Nikki on 82 GSL was messed up....I got it rebuilt, stripped of everything...and because I did not wanted any other problems went with mechanical secondaries.....

You should consider that if you can't find the problem.....

Eastman51

I feel like mechanical secondaries don't fix the problem. They just ignore the problem.
Not like mech secondaries would solve anything right now anyways since the car can barely run with the choke right now....

raven12aFB

They'll fix the vacuum problem because is not needed ....

Eastman51

.....

mazdaverx713b

iTrader: (91)

Keep us updated on what you find.

Eastman51

It's rainy today and I will be busy this weekend, so can't do anything that requires carb removal (I need a garage, lol). If I find time sunday afternoon, I think the weather is going to be better.; otherwise it shouldn't be rainy on monday after work. However, I did do a little bit of testing with the carb on the car today.

As the throttle adjustment sits, the primary blades are opening all the way; so I don't think that's my issue. Likely the gasket being installed incorrectly like was mentioned.
Manually actuating the secondaries works great, engine is VERY happy with it.

The car sat since the last time with the fuel pump unplugged and the carb bone dry. Plugged in the pump and tapped the carb with a hammer and it wasn't leaking fuel. Ran really nice off the choke. But still back to the idle issues, and no secondaries under load makes it a dog to drive. Could be the weather or idle issue, but something just feels *off* about driving it; even staying under 4k.


When I blip the throttle in the engine bay, I see the accel pump and primary jets working just as intended; but it bogs and makes a weird noise. If I drive around still, then push in the clutch, it nearly stalls out before making its way up to 1k rpm idle. I sprayed carb cleaner at all my vacuum connections and they seem all good; however idle slightly increases when I spray around the idle mix screw. I suspect maybe a carb spacer gasket issue or something of the like?

I'm a carby noob, so all I know is that I rebuilt the carb per the manual's instructions. If there's any tricks the manual doesn't mention, or anything I should test out/look at when I check the gasket for the secondaries, PLEASE let me know!

Eastman51

I think I have fixed the issue, mostly.
Turns out the main body gasket was flipped. It had also been gas soaked and was ruined. One of my buddies said he could make me a gasket and whipped one up.

The secondaries work now, go figure lol.
And the idle issue is mostly resolved. I might have a vacuum leak or the plugs have fouled from how rich its been running. Idle is unsteady and while I can get it under 1k rpm, I can't make it hold speed; just wants to bounce up and down.

The really weird thing now though, is that all of a sudden the choke has become extremely stiff. I can barely pull the lever in the car, and it has a lot of resistance when trying to actuate the choke plate at the carb itself. I think I can take the choke system apart without having to take the carb off again, so I will be checking it over today to see if maybe there's a problem with the fast idle rod or the heater thing.

mazdaverx713b

iTrader: (91)

Glad you were able to find the issue with your secondaries. I had that happen to me once and someone suggested I look at that gasket and they were spot on. Figured I'd pass that tip along to you as well.

You should be able to check the choke linkageleith the carb on the engine. It sounds like something is bound up.

Eastman51

Yes, I appreciate the tip!
I checked the choke linkage yesterday and it seemed fine. Really weird how it was stiff on sunday. I lubed it up with some lithium grease just in case.

I did some playing around to try and find why it has such an unstable idle and think I narrowed it down to the shutter valve; however one of the floats/needles decided to get stuck conveniently after I figured that out. However its also possible the shutter valve is fine, after all I checked the solenoid operation and wiring the coasting valve to constant vacuum didn't seem to improve conditions much. Once its not flooding, I'll try it with the shutter valve hooked up correctly.

These floats are such a pain. Pretty sure my carb has always run rich too, so the floats may need adjusted; but I am just so hesitant to start playing with that.

mazdaverx713b

iTrader: (91)

Its recommended that the float adjustment not be altered. I have played with this theory as most are out of adjustment when rebuilding the carb. I use a caliper to check depth given the position per the FSM. I've adjusted some within spec and the car has run great and others not so much. Many guys here will advise against adjusting the float level. If you already did adjust them and are having issues, you will want to recheck your adjustment. If you need the spec let me know and I'll send you or post here, a picture of the adjustments and procedure.

Eastman51

So, I took the carb back apart and adjusted the center tangs that touch the needles within spec. And that seems to have fixed the flooding. I did not mess with the other tang that controls droop, though they seemed to be out of spec.

However, I cannot figure out what the hell is wrong with my idle. It acts as though there is a vacuum leak, but I cannot find one no matter where I spray carb cleaner... If I get the idle speed under 1k, then it just runs poor and eventually stalls out. But if it idles over 1k its mostly fine.
When driving around, if I put it in neutral when I begin to stop (this can be after downshifting a couple of times as well) then the rpm dips really low before jumping up to the high set idle. Then it kinda goes up and down marginally. It occasionally bogs when shifting into 3rd or 4th while driving casually and normally; shifting around 4k and/or the shift points listed in the owner's manual.

I didn't get a chance to replicate it, but today while ripping onto the highway it was doing great up to 7k in 1st and 2nd gear, but when I hit about 6k rpm in 3rd it hit a wall.

Do I need to adjust the droop of the floats? Or is there some other problem?
Maybe I just need new spark plugs? It has been flooded an awful lot...but I don't think that would fix it?
I'm awfully lost at this point. Just when I think I get things figure out, its still not right.....

Eastman51

Well I'll be dipped.

So, the last remaining issue was the spark plugs; or at least its fair to assume that since I haven't actually replaced them yet.

It snowed on Sunday, didn't stick and the city didn't salt. So its time for the car to go into storage, and what better way for the car to give a last hoorah for the year than to risk it and drive to work one last time. Its supposed to be quite nice this afternoon....

Warm it up for 5 minutes and set off, and manually release choke (since its been way too cold for it to do so on its own last few times) right before getting on the highway. Just drive casually on the highway, cruising a nice 70mph.
After about 15 minutes or so, get off the highway to take country roads the rest of the way; idle doesn't dip. Just falls and rests at 1100 rpm, no loping or excessive missing. Just, perfect. Absolutely nothing else has changed since my last post.
I will have to stop for gas on the way home, so I will dial it down to 800rpm when I stop.

The only explanation that makes sense is that the spark plugs cleared up and sort of un-fouled by running consistently at a good pace and load. It didn't seem logical since it was acting like a vacuum leak would, and everything else keeping it from running good to this point was the carburetor; but at the end of the day, hindsight is 20/20. My unconscious hunch was correct! I will replace the plugs when the car comes out of storage in the spring.

Thanks for the tips and help mazdaverx!

I will also make note of this since I realize I did not make it clear in my last post:
I had not messed with the floats at all to that point. I went with the "don't touch 'em" approach. I was careful with them at all times, and after swapping back to the old needles the floats looked fine. Was even told by some people in another social outlet that they looked "close enough to not cause issues." But for whatever reason when I took the carb apart last Friday, the floats were wildly out of spec. Putting them in spec when the air horn is held upside down solved my flooding on the first try. In best practice I should probably take the carb apart one last time to adjust the droop when its held upright, but its probably fine. I measured it and they seemed about 5mm too high (going off the spec in the carb manual). When held upside down, I forgot to see how far off they were; but I would guess they were about 2-3mm too low. No wonder it was flooding! Still not sure how they got messed up, but all is well in the end.

mazdaverx713b

iTrader: (91)

Glad to hear its running much better! Sounds like your adjustments are now spot on and a little carb tweaking will be in order. I was going to drive my 10th Anniversary RX-7 to work today but decided to take my Corvette instead. The roads were somewhat wet for whatever reason but I was pleased with the trip. Nice to have some decent temps this late in the year in Ohio, especially up north where I live. If the weather is good later in the week I may take my 85 RX-7 to work.

Eastman51

Certified Ohio moment..

Anyway, last post on this issue.
On the way home the car acted up again with the whole rpm dips and funky idle. But it's still all good. Pulled out my box of old spark plugs and cleaned up the best looking 4. Ran perfect immediately. Dialed in idle and got my throttle cable adjusted.
It decided to get pissy and one of the floats got stuck, but I got it unstuck by unplugging the fuel pump and letting it run dry; then tap the carb lightly and plug the fuel pump back in.
I can tell she wants new plugs, but I'm happy with how she's running for the moment.
Dropped the car off at the storage unit with a full tank and treated with fuel stabilizer; hopefully I don't have to rebuild the carb again!

Toruki

Glad you got yours sorted. Yesterday was beautiful here in MA as well. My FB is already in the archive for the Winter or I would have had it out. And FWIW, my 83 FB "grew up" in Cleveland before moving out on its own to me in 2010.

With yours going into storage, here is an excellent thread on prep for that. Tese tips fortify the FB for outdoor storage in Winter...in Alaska! Yours is in a garage unit apparently, so some things might be unnecessary.

https://www.rx7club.com/1st-generati...orage-1087914/