How do I get this out? It a Hitachi off of an EA82. Underneath it is the idle adjustment screw.

 

It almost looks like just a soft plug.

 

http://picasaweb.google.com/pmilne/Misc/photo#5104288466642083922

It is just a soft rubberish plug, just pry it out. HOWEVER..........,that's not the idle adjust screw, it is the mixture screw. Not advisable to mess with it. It is tuned to match the engine and sealed at the factory(that's why the plug is there)

 

But if you want to it is Clockwise to lean, CounterClockwise to enrichen mixture. But if you don't have an exhaust analyzer you're just guessing, adjusting the screw makes almost no noticable difference to the way it idles or revs. You'll be trial and error, seat of the pants adjusting, and could end up with terrible gas milage and/or even overheating(too lean)

Sorry, I meant idle mixture screw. :/

 

I am rebuilding the carb and I WANT to get at it. I figure if I am going to go through the fuss of a rebuild, I ought to at least see what the screw looks like.

 

The rebuild kit says something like 4 turns from a soft seat.

Sorry, I meant idle mixture screw. :/

 

I am rebuilding the carb and I WANT to get at it. I figure if I am going to go through the fuss of a rebuild, I ought to at least see what the screw looks like.

 

The rebuild kit says something like 4 turns from a soft seat.

 

It's not a moving part. It will look excactly like it did when it was sealed at the factory. 4 turns off a soft seat may get you close to a good mix, but again without an exhaust anylyzer it's a guess. If it ain't broke, And it's not supposed to be messed with, Iwould not mess with it. I did it once and I ended up having to take the car to a shop with an anylyzer to set it correct again before it would pass emissions. Really there is no reaso to mess with it.

Well, I do believe there is a replacement one in the rebuild kit. Not positive, but thought I saw one.

Well, I do believe there is a replacement one in the rebuild kit. Not positive, but thought I saw one.

 

Just because a new one is furnished, does not mena the old one needs replacing

Carb is back on and one thing I need to mention. The air mixture screw did need adjusting and it does make a noticable difference, adjusting by ear. I dont have a purring idle, instead of a lumpy one.

u mean the idle screw. Thats something you can do by ear and can mess with. I had to hike the idle up on my hitachi a bit. If its too low the car will idle like a tractor.

No, I mean the idle air mixture screw that is normally blocked by a plug.

 

http://picasaweb.google.com/pmilne/Misc/photo#5104288466642083922

Carb is back on and one thing I need to mention. The air mixture screw did need adjusting and it does make a noticable difference, adjusting by ear. I dont have a purring idle, instead of a lumpy one.

 

Purring Idle does not mean the correct mixture. It could be way lean and still idle great. Without an exhaust gas test there is no way to tel if you have a good mixture.

It's not that we want to tell you what to do with you're own car. But don't fool yourself into thinking that "it sounds good" means that you have it right. Every piece of literature about Carbed Subarus warns in big black letters NOT to adjust the screw, espescially without tools to measure the exhaust mixture.

I suppose you could measure the mixture by fitting an O2 sensor, and measure the voltage produced, then compare it to the specs for an SPFI or MPFI cars *ideal* voltage range. If you do end up with a lean mixture watch you're temp, and pray for you're pistons.

Just call me an idiot......................

 

When you rebuild a carb, you completely disassemble it before soaking it in the cleaning tanks, this includes all jets and screws, mixture, or otherwise.

 

The idle mixture screw is just that, it adjusts the mixture at an idle. Pre environmentalist/government rip-off BS you would alternate between this screw and the idle speed screw (after making sure the timing is set first) to get your idle speed correct. You would adjust the idle mixture for the highest/smoothest idle first, then go back to the idle speed screw, adjusting for correct speed, then back to the mixture screw to re-check, then do a final on the idle speed.

 

Did it this way for 20+ years.

I am sure you know there is a set rule for adjusting a carb by ear. First, you need to take into consideration elevation. You dont have that issue in Wisc. Here, we run 3000-6000', which these vehicles weren't tuned or jetted for. Higher elevations is going to richen your mix due to thinner air.

 

When you do adjust a carb by a tach or by ear, you can get it to its highest rpm, then to be safe, you can richen it a little bit, from there. This is how we did it in the days before all the fancy gadgets. Dwell meter and a tach.

 

We do this for all 2 strokes and for any other older vehicle that was equipped with a idle mix screw. You are correct though, too lean is bad. I dont recall ever seeing a 4 stroke that you could adjust too lean. Checking plugs is a good gauge when in doubt. Anyone that is mechanical should be able to tell when their rig is running too lean or too rich.

 

Gas analyzers? Not to be found in this area.

Gas analyzers? Not to be found in this area.

 

Are you kidding? They aren't rare or exotic at all. It's staple tool of professionals everywhere.

Here, we run 3000-6000', which these vehicles weren't tuned or jetted for. Higher elevations is going to richen your mix due to thinner air.

 

 

If it was sold new at high altitude, it WAS equipped and adjusted for it.

Are you kidding? They aren't rare or exotic at all. It's staple tool of professionals everywhere.

 

You mean a 'sniffer' that goes up the tailpipe?? I've not seen one here. I dont doubt that they are everywhere in the populated areas. Heck, we just got colored TV here last year.

Not to interrupt.. but I think i might be running to rich were is this screw?

Under this plug:

 

http://picasaweb.google.com/pmilne/Misc/photo#5104288466642083922