Having read dozens or more threads on the topic in the past few months, posting this to see what gets added. I bought and installed a brand new 5 or 6 year old Sterling carb a couple months ago. It replaced my stripped Nikki w/ accel pump mod, which I thought was pretty sweet.

The Sterling is amazingly driveable, pulls beautifully from 2000 to well past 7000. Great throttle response at any speed. Drinks gas like I used to drink whiskey. No worries there, I'm not looking for economy.

But the idle is essentially non- existent. Currently it "idles" at 1500 w/ the AC running, 1800 or so without. To this I am resigned. I have read some threads that mention the incompatibility of some different year metering plates and bodies, and can only assume that this is my issue.

I have my stripped Nikki, a parts Nikki, and 2 other "good" Nikki's. Just wondering what suggestions the board might offer.
Thanks.
Sent from the coffee shop, right after work.



Edit: Just noticed I posted in the wrong area.
Sorry 'bout that.

 

https://www.rx7club.com/1st-generati...t-idle-991744/

Don't know how I'd missed this one.

 

hmmm. lots of stuff done in that thread, but no obvious solution presented... that I could see.
??

Stu Aull
80 GS
Alaska

 

Ah, you figured out that the TBs are different from different years. Not knowing which year parts your Sterling has, you should try swapping TBs until you get a decent idle. Then see if it's possible to trim down the screws and shafts so it flows more like an actual Sterling and less like a stock Nikki. If that's too much work, at least trim the screws. They're really long and big in FB Nikkis!

Oh and save the Sterling TB for one of your other parts carbs. You may get two nice running carbs out of this endeavor.

 

If you're getting horrible fuel economy, your car is NOT running well.

A stockport 12A with a nice exhaust and tweaked carburetor should see 27mpg minimum. I've seen 30 on a regular basis and did 33 once.

Hell, the bridgey 13B is putting down 25mpg with a high of 27. It's not tuned Sterling style IE "throw fuel into it and then more fuel and some extra fuel on the side because FUEL = POWAR".

 

I loved my Sterling. You need to check your jets and vacuum leaks. Throttle plate clearance etc... Buy a rebuild kit. Rolling at 20 MPH in 2nd then stomping the gas opening the secondaries...WAHHHHHH!!! Shift into 3rd at 7000 RPM the tires go CHIRRRP!!

 

Yesterday I swapped my stripped Nikki back on. As good as it ever was. When time permits I'm gonna swap some throttle plates and see what happens.
NCross, yeah, it's like that. But no idle. I'll figure it out. In time.

 

Today I assembled the Sterling with my known to be 1985 body, the sterling throttle plate and top. Started, ran on AP only. Disassembled, cleaned, reassembled, same. Pulling no fuel through primaries. Secondaries yes, as several burnouts in the street in front of the house proved. But I can't drive like that, neighbors and all, ya know.

Back to the drawing board, so to speak.

The throttle plate on the Sterling has 36 cast into it. My 85 has 37 cast into it, and my parts carb has a 3. Does anyone know what the number cast into the plate means or represents?

 

Check your air bleeds and emulsion tubes for clogs as well as your jet passages.

 

Oh yeah, I do it right, I do it 3 or 4 times. More if required.

 

What size jets are you running? I would recommend putting the stock air bleeds back in. If I remember right, I found that if you re-drilled the stock primary jet to 0.048" it works the best on primary and stock 160 to work best on secondary. Youll need a very precise drill set. After you drill take a tooth pick and spin it around in the hole to smooth it out since brass is soft. If your air bleeds are too huge the fuel jets wont be able to supply fuel.

 

What I had assembled was the top and the throttle plate of the Sterling with my stock Nikki middle/Venturi section. All jets and bleeds stock. It wouldn't pull fuel through primaries.

I then reassembled my Nikki, installed, and it magically runs better than ever, idle at 650 with the AC running.

I'm gonna let the Sterling rest. I really like driving the car more than I like tinkering with it.
Sterling said his carbs required commitment on the part of the owner. I may be spread too thin already. But it (the Sterling) sure is nice above 3000 revs.

 

that was my old thread... put the sterling carb back together like it was when you bought it. keep turning the air fuel screw out until you get a decent idle, way out. like 6 turns. it takes some tuning but it should come down. set it until you get a good idle, then screw it out and then drop the idle down. i can almost guarantee it's not getting enough fuel at idle and that's why it dies below 1500rpm. 1500rpm it's pulling fuel from the primaries and not the idle circuit.

 

Cshaw, the Sterling is back together, and some day in the near future I'll reinstall and see how that (6 turns) does. Sterling said 1/8 turn was the starting point for the idle mix screw, I don't think I went past one and a half.
As of now my Nikki is so good I just wanna drive for a while and enjoy.

 

ok. let me know, i did A LOT with the sterling carburetor trying to figure it out, it's been running PERFECTLY for the past 30k miles however you do have to make small adjustments, especially when the weather goes from 35 in the morning to 80 in the evenings. like i said, if you get a good idle at 1500rpm, put it there. then start turning the air fuel screw OUT by about a half a turn each time, then try to lower the idle with the idle screw. if the idle wont come down and it just dies (i'm assuming that's what happens to you) unscrew the air/fuel screw a bit more. your idle should start coming down and not stall. keep doing that until it's at about 750rpm, then fine adjust the air/fuel screw by 1/4 turn each time. what you want is the idle mix as lean as possible, turning the air/fuel screw IN leans the mix. when you get it to 750rpm, turn it in by 1/4 at a time (give it a few (30ish) seconds to adjust) you want it to start to stuble and run sorta bad, then turn it out 1/4 and leave it there, it should be set perfectly. this screw is touchy, i bet when you adjusted it the first few times you tried it didnt do anything, right? (a guess) i seriously thought I had a very shitty **** poor sterling carb, especially when everyone else says they slapped theirs on and it was fine out of the box. but now i can make my car idle at 500rpm without stalling if i want, but i keep it at 750 because it's what it's supposed to be at. good luck, keep on rotorin!

 

Cshaw, thanks for the reply and words of encouragement. If only I were unemployed with no family I'd have a little more time to spend on it. I'll get it sooner or later.