My 1980 BRAT idles at 1400 this seems really high to me and I can not get it to go down (was at 2k when I started but now lowered when giving it full throttle it goes the chokes for a second and goes real hard) by messing with the adjustment screws on the carb and i cant find anywhere that says or shows how to tune a carb (this is my firs carbed car I do not know anything) I am also wondering what the air/fuel ratio should be for this car.

I have found the idle speed screw but I cant not find the idle mixture screw to save my life, my carb matched every picture I have seen of the stock hitachi carb for the 80 brat but they show the mixture screw next to the idle screw if I lower the idle anymore it dies and my air fuel ratio meter says it is as lean as the meter will read

try finding a factory service manual, or someone who has a link to one.  There should be a step by step procedure in there.  1400 is really high, if it's all warmed up.  I've never had an 80 with a carb, so I can't be much more specific.

Sounds like the idle stop solenoid is inoperative/unpowered or the idle circuit in the carb is otherwise blocked.

Check for power at the solenoid.It should click w/applied power.

If it is fubared,you can gut it to open the idle passage.

Edited October 21, 20169 yr by naru

http://www.autozone.com/repairguides/Subaru-ff-1-1300-1400-1600-1800-Brat-1970-1984-Repair-Guide/Carbureted-Fuel-System/Carburetor/_/P-0900c15280065ae8

http://www.autozone.com/repairguides/Subaru-ff-1-1300-1400-1600-1800-Brat-1970-1984-Repair-Guide/Carbureted-Fuel-System/Carburetor/_/P-0900c15280065ae8

I have read that my carb has two adjustable screws one controls where the throttle return stops the other is idle speed

 

 

this is the carb on my EA71 engine

 

 

 

that long slotted screw under the throttle arm is the Throttle return stop

 

 

 

 

 

 

that flat head screw is idle speed these are the only screws i see on this carb that dont take it apart  

 

sorry its rotated I cant figure out how to fix it

Long one is the throttle stop/idle speed screw.

 

Bottom one is the idle mixture screw.

It only adjusts idle mixture and will have no effect above about 1000 rpm as the carb will be running on the main

circuit rather than the idle circuit.

 

Check the solenoid.

Long one is the throttle stop/idle speed screw.

 

Bottom one is the idle mixture screw.

It only adjusts idle mixture and will have no effect above about 1000 rpm as the carb will be running on the main

circuit rather than the idle circuit.

 

Check the solenoid.

is the solenoid the part withe the wire coming out of it in the last photo? 

 

whenever I turn the screw you say is idle mixture it just changes the rpm

As I am sure you have found this is my first carbed vehicle and I dont know what I am talking about, the idle is down to around 950rpm but the mixture screw is turned all the way in which would be it running extremely rich right? If I losen it any then the rpm goes to about 2k and it will not go any higher than that

 

So I am assuming that I need to put the mixture screw back and move the choke to bring the idle down and all while it is doing this the engine is running on the choked side of the carb till I give it any amount of gas and it stays at that rpm but the other side of the carb starts using fuel

Yes,that is the solenoid.

It is normal for the rpm to change w/mixtiure changes.

I`m surprised it has any effect at that rpm.

Since the engine responds to idle  mixture changes,that suggests the solenoid is OK,
I`d check it anyway.

 

I`d be checking to see if the secondary throttle is hung open.

Recently had one w/high idle for that reason.

As I am sure you have found this is my first carbed vehicle and I dont know what I am talking about, the idle is down to around 950rpm but the mixture screw is turned all the way in which would be it running extremely rich right? If I losen it any then the rpm goes to about 2k and it will not go any higher than that

 

So I am assuming that I need to put the mixture screw back and move the choke to bring the idle down and all while it is doing this the engine is running on the choked side of the carb till I give it any amount of gas and it stays at that rpm but the other side of the carb starts using fuel

 

Mixture screw all the way in means the idle circuit is getting NO fuel.

A rough adjustment would be 2-3 turns out from bottomed.

Don`t bottom it hard,they are delicate.

 

Choke has to be wide open and the idle speed screw should not touch the fast idle cam w/adjusting idle speed and mixture.

Do a rough adjustment on the mixture and then see if you can reduce rpm w/the speed screw.

The solenoid works it shot the pin across my garage

Aww man thanks so much it runs so well now it doesnt sound bad or shake badly on start

 

Edited October 22, 20169 yr by Divisible_By_0

Idle solenoid? They don't have an idle solenoid. Some had an idle up vacuum pod if it had AC. That solenoid is the anti diesel or shut down solenoid. All it does is open on key on and close on key off to stop fuel in the idle circuit. Other than shutting off fuel, it has no effect or control of idle speed.

Idle solenoid? They don't have an idle solenoid. Some had an idle up vacuum pod if it had AC. That solenoid is the anti diesel or shut down solenoid. All it does is open on key on and close on key off to stop fuel in the idle circuit. Other than shutting off fuel, it has no effect or control of idle speed.

 

Also known as an idle stop solenoid.

It will kill the idle if it does not work. Plenty of effect on the idle speed.

Aww man thanks so much it runs so well now it doesnt sound bad or shake badly on start

 

Cool!

Right. As I stated, other than shutting off the fuel... It can't cause the car to idle up. That was my point.