My '84 GL wagon starts fine, idles okay (has a bit of a miss - I'm going to replace the spark plugs and see if that helps), then dies as soon as it's warmed up and out of gear. It'll idle at 1,500-2,000 rpm cold, but once I've driven maybe a mile it will not idle at all. I can start it right back up as long as I apply a little pressure to the gas pedal, but as soon as I lift off the gas, it dies again. When I bought it in September, this was not a problem. It seemed to idle too high when warm, but it wouldn't die. I drove it a couple times, probably 30-40 miles each, then the next time I drove it the problem started.

Does this sound like an issue with the carburetor (I believe it's a Hitachi)? Does it need to be cleaned or adjusted? Or could it be something else?

Also, I would have messed with the idle adjustment screw, but I can't find it. I don't really know what I'm looking for, and I haven't been able to find any photos or videos that identify the idle adjustment and air/fuel mix adjustment screws.

Any advice would be greatly appreciated. Right now I don't even know where to start.

Thanks!

Shouldn't need to mess with the idle screw.  If it has one.  That doesn't suddenly change like that.

 

Is the choke opening properly when it warms up?

Many things could cause the problem you are experiencing....

 

Did you buy gas just before the problem started ?

When were the fuel filter(s) last changed ?

Have you checked the air filter ?

Try cleaning and sharpening the plugs before spending money on replacements.

Have you checked the distributor to make sure the contacts are clean and the rotor is in good condition ?

 

Check you temperature switch. Unplug it and if motor stays on then you would have a bad sensor. I had that issue with my 84 wagon

I'm not sure about the choke. Looking down the carburetor with the air cleaner off, I couldn't see any difference between when it was cold and running fine and when it warmed up and wouldn't idle, but I don't really know what to look for either (I'm new to carburetors).

As to the gas, the problem started before buying new gas and has continued with new gas. The previous owners had it about a year and didn't really drive it or work on it, and I have no idea what the owner before did and when. Not knowing the maintenance history and with the idle issue, I just replaced the two fuel filters and the spark plugs (I already had a new set on hand), but nothing has changed. The air filter is fine, but I don't know about the distributor contacts and rotor. Could you tell me what/how to check there?

I think I unplugged the right wire for the temperature switch (picture attached), but the engine still died once it warmed up as before.

Any suggestions/ideas on where to go from here?

One thing I forgot to add before is a picture of the old spark plugs. I don't know if this provides any insight for the problem I'm experiencing, but the old plugs were black and sooty.

On 1/3/2021 at 2:11 PM, GLwagon1984 said:

I don't know about the distributor contacts and rotor. Could you tell me what/how to check there?

Take the distributor cap off.  For each plug contact in the cap clean with very fine sandpaper or emery cloth, so there is no oxidation on the metal contacts.  On the rotor, clean the metal contact also.

3 hours ago, GLwagon1984 said:

...plugs were black and sooty

Carbon fouled

Black, dry soot on the electrodes and insulator tip indicates a carbon-fouled plug. This can be caused by a dirty air filter, excessive driving at low speeds, too rich of a fuel/air mixture or idling your vehicle for too long.

 

The choke is the top butterfly valve in the carb.  It should snap closed when cold when you tap the gas pedal before cranking.   It should be wide open once warmed up.

21 hours ago, Dee2 said:

Take the distributor cap off.  For each plug contact in the cap clean with very fine sandpaper or emery cloth, so there is no oxidation on the metal contacts.  On the rotor, clean the metal contact also.

 

Thanks! I'll give this a try.

9 hours ago, DaveT said:

The choke is the top butterfly valve in the carb.  It should snap closed when cold when you tap the gas pedal before cranking.   It should be wide open once warmed up.

So, the picture below is what it looks like as soon as it's started cold and once it's warmed up (and won't idle) - nothing changes as far as I can tell. It seems to me that the choke is not opening properly as you suggested earlier. Correct me if I'm wrong, but that looks like the butterfly is not opening like it should.

If I understand correctly, if this is the problem, it should not only cause the idle issue, but also make the fuel/air mixture richer, and cause those carbon-fouled plugs.

You got it.  The choke looks closed.   That would not run well at idle warm, and run very rich.   Check the heater in the housing to the left, that is what causes the bimetal spring to open the choke as it and the engine warm up.  Also, check that it moves freely.   The butterfly should be near vertical when up to temperature. 

Now that I've got some free time and decent weather for working on the Subaru again, I'm back to trying to get it to stay running. I did manage to get the choke to open with just a few shots of carburetor cleaner, but I'm still having problems.

When I start the car cold, it idles at about 2,000 rpm for maybe 30 seconds or so, then the choke opens most of the way and rpms drop to 1,200-1,500. At this point, if I give it a little gas, as soon as I let off the gas completely, rpms drop like a rock and it dies. So I tried just letting it idle without touching the gas pedal to see what would happen. It stayed around 1,500 rpm for a couple minutes, then began to climb slowly. Once it got up around 3,000 rpm, I put a little pressure on the gas pedal and let off, and again it died.

I have no idea what to make of this, so if anyone has ideas, I'd love to hear them. I don't know what to try next.

Also, I did check the contact points in the distributor. All looked clean, but I went over them with some fine sandpaper just in case. The air filter appears to be new, and is very clean, so no issues there that I can see.

It sounds like it has been sitting for long stretches?  The idle passages could be gunked up.

I don't see anything in your destination that Points to electrical / ignition problems. 

I don't know specifics about EA81s, I  skipped over those years.  EA82 Hitachi carbs are a real problem to rebuild. 

Always assume carburetor until you’re sure it’s not. It’s always the carb

If you don't have a service manual, then to find out how to adjust your carb, look here:

http://www.suberdave.com/USMB/HTKYSA.PDF

Chapter 7 procedure 12

It was idling well previously and nobody else adjusted the screw.

Check the float bowl and clean the needle and float chamber well. The real way is to remove the carb and soak it , blow it out , etc. But if you just take the float chamber cover off and work from there you’ll likely be fine. 

Service manuals are out there online or hard copies. 

 

Thanks for all the input!

I removed the top of the carburetor, shot it with plenty of carburetor cleaner, and tried to clean everything I could get to about as well as I could with the carb still on the manifold. When I put it back together, there was no change.

The inside of the carb still looks filthy, the gasket material is disintegrating, and since it still doesn't run right, I'm thinking it might be time to get a carburetor kit, pull off the carburetor, and clean/rebuild it. Does anyone have suggestions for a brand of carb kit and/or where to buy it?

Kits are out there too. 
 

Be sure to read up on what I was indicating to you. I did not go into detail but assumed you would check and adjust the float. 
 

From your description I would say remove the carb and soak it, do it properly. And when you’re all done check and adjust the float. You’re likely going to remove the top cover more than once and the adjustment can be frustrating so go slow and follow the manual. 
 

Your carb kit will almost certainly have an instruction sheet which helps a lot. 
 

Good luck. 

On 4/3/2021 at 10:10 PM, moosens said:

Service manuals are out there online or hard copies. 

 

What is a good online source? Needing a copy of my own...

6 hours ago, 6 Star said:

What is a good online source? Needing a copy of my own...

Subaru Service Manuals

Edited April 7, 20214 yr by subaru1988

19 hours ago, moosens said:

Kits are out there too. 
 

Be sure to read up on what I was indicating to you. I did not go into detail but assumed you would check and adjust the float. 
 

From your description I would say remove the carb and soak it, do it properly. And when you’re all done check and adjust the float. You’re likely going to remove the top cover more than once and the adjustment can be frustrating so go slow and follow the manual. 
 

Your carb kit will almost certainly have an instruction sheet which helps a lot. 
 

Good luck. 

Thanks!

I'll certainly read up and watch any videos I can find before diving into it.

referring to the picture in the Jan 3rd post - the tab that the wire connects to broke off of the thermometer thermistor for the temp gauge.

What about just replacing it with a simple Weber carburetor? If you want to keep the stock look, just adapt your air filter housing to it. Just my 2 cents.

17 hours ago, subaru1988 said:

Subaru Service Manuals

Thank you. Lets see if those elusive part numbers I'm searching for are between those pages...

14 hours ago, 6 Star said:

Thank you. Lets see if those elusive part numbers I'm searching for are between those pages...

You need part numbers ? 
 

I tend to forget sometimes but I do have my factory parts manuals/catalogs at home currently. Let me know which ones you need , which year vehicle and model , the usual stuff.