This has been a problem for a long time and I’m out of ideas. Carburetor is a weber 32/36 DGEV.
I have the fast idle set to about 2300rpm. Idle speed is at 1000rpm.
When it’s cold I pump it once to the floor and it starts and runs at 400rpm for a few seconds then dies.
To get it warmed up I have to pump it, hold the accelerator pedal half way down, then start and hold it at 2000rpm for 30 seconds. Then I shut the car off, pump it once more to set the fast idle, then start it and it will idle in its own at 2300rpm.
It runs great once it’s warm.
Things I’ve tried: fuel filter, plugs, wires, coil, new battery, carb rebuild, different carb jets, I’ve removed and capped all vacuum lines except one the ecu uses to adjust the timing. New distributor, timing set to 5 btdc. New coolant temp sensor.
I installed a fuel pressure gauge right before to carb, and it is at 3psi as soon as I turn the key on. It drops to 1.5psi at highway speeds, I’m guessing that’s normal. I’ve adjusted the electric choke according to the manual and it looks like it’s functioning properly. I’ve set the mixture control screw according to the Weber instructions and believe I have the proper jets installed.
I haven’t found anyone around Duluth that wants to touch a carburetor.
It doesn’t matter if it’s 80 degrees outside or 0, it acts the same.
there is a nice solid stream of fuel from the accelerator pump.
I’m leaning about carburetors as I go, so I may have overlooked something. Any ideas on where to look next or things to recheck are appreciated.
This is not much help , but you might try asking a hot rod speed shop with some older mechanic to rebuild your carb. You may have the only Justy left on the road.
Have you checked that the primary choke pull-off is operating properly?
Tester
Indeed!
But, overall, after 28 years of service, it is undoubtedly time to retire this econobox.
Please don’t fall into the trap of thinking that I look down on Japanese marques in general, or Subaru in particular, because I am currently driving my third Subaru. However, you are trying to drive the absolute cheapest-ever creation of that company, your vehicle is now 28 years old, it was never designed for service of that length, and its “technology” is not well-understood by any currently-working mechanic…including those at a Subaru dealership.
The bottom line is that, at some point, one needs to disconnect from an older car with little or no technical support, and I believe that you have reached that point.
If you are satisfied with the way it runs after using your procedure I suggest you carry on and save the cost of repairing it. But I suspect that the linkage is either out of adjustment or binding.
I agree.
The fact that it maintains its proper 2300 rpm after playing “the gas pedal game” suggests that the temp sensor that sets the high idle and the choke is functional, although perhaps sticking (the bimetallic springs can rust) or that the linkage is sticking, generally this happens in the high idle cam linkage. It is, however, possible that the sticking is happening in the choke shaft itself. The shafts can wear a groove where they transcend the carburetor body and hang up there… as can the throttle plate shaft.
It’s unfortunate that you’re unable to find a shop in your area that’ll touch carburetors.
Have you gone to the Weber carburetor website to look for information? I found this (see link). By starting with the auto choke body assembly (51) you can, with a bit of study, follow the linkages and see exactly what’s involved in this mechanical process. I guess if I couldn’t find exactly what’s binding, I’d start by replacing the temp sensor (electric choke control assembly, item 99).
NOTE: since you apparently have an electric choke, item #48 will have been replaced by item #99, and the water supply parts will not exist.
I’m sure there must be a rebuild/repair procedure available too. As a matter of fact, it’s listed in the parts list in the link.
Just a quick question here, do you turn the key to the run position (not start) before you first push the gas pedal to the floor and release, then start the engine?
I like that question. It is possible that you’re draining what’s left of the fuel in the float bowl when you initially pump it and it then has to refill again… which suggests that the line is draining.
The '89 should have an electric fuel pump. If you turn the key to ON a few times for a few seconds each before turning it to START and the problem disappears, that’d pretty much point to the line draining. Doing so would allow the pump to refill the fuel line.
That could be it but I was thinking that the electric choke needs both electricity and depressed gas pedal to set.
That’s true, but it should have power when the key is turned to START and the OP said the pedal was depressed.
You did, however, point out that I didn’t differentiate the difference between the water choke and the electric choke, both options of which are illustrated in the exploded view drawing. The OP did say that he’d adjusted the electric choke, which would change my suggestion to changing item #99 rather than #48.
NOTE: I’m going to add another possibility to check, and that is that the float bowls may be mostly draining out when the engine is off. There might be enough to support the accelerator pump and prime the system, but not enough for the engine to keep operating until the bowl fills up again.
As to the pressures, these should be correct. A carburetor requires only the fuel pressure in its supply to keep the float bowl filled and no more. Rather than push fuel to the engine, as injection does, it simply keeps the float bowl full and allows the engine to draw the fuel through the small orifice past the venturi, where the lateral wall pressure of the passing air drops. It basically operates on the difference in pressure between the weight of the fuel in the bowl and the lateral wall pressure in the carburetor throat. That little three-cylinder engine doesn’t draw much fuel, so it doesn’t take much line pressure to keep the float bowl full.
I like Justys. I helped a friend fix the engine up and do the brakes on his years ago and got to drive it. I liked it, thought is was a fun car.
In the days of carburetors with automatic chokes, the standard practice was to floor the pedal and release, then start. This is not the OEM carburetor, its aftermarket. Where the choke gets its power depends on where the installer decided to take it from. Generally only the starter motor and the ignition have power when the key is in start position. Everything else gets power from the run or acc positions or is hot all the time.
Here’s how a carbed choke system should work.
Step on the gas pedal and the choke plate should close completely.
Start the engine, and the primary choke pull-off should slightly open the choke plate so the engine idles.
Step on the gas pedal, and the secondary choke pull-off opens the choke if you wish to drive the vehicle.
Tester
It sounds like the cold-run condition is the only problem. It starts ok cold, but just won’t run well until the engine warms up, right? I tend to concur w/Tester, that symptom is consistent with the choke pull-off function. At least on my Ford truck’s carb, the carb supposed to cold-start with the choke plate fully closed, then immediately after the engine starts, the choke plate should open slightly, like 1/8 of an inch, open, but just barely. The choke pull off is done w/a vacuum operated gadget on my truck, and if the diaphragm that operates the vacuum motor ruptures, this symptom could develop.
One idea, surf around if there’s any kits available that allow you to turn this into a cable operated manual choke system. If the choke pull off diaphragm is split, you’d still have to fix that b/c it would create a vacuum leak.
Another idea, 1980’s Subaru carbs had a failure mode that was very difficult to diagnose. My parents had that problem, and they finally just sold their Subbie to the mechanic. As I understand the issue, it has to do with the electronic control of the Subbie carb. This design complication is used for emissions and drivability reasons, and affects how the carb is configured as a function of ambient and/or coolant temperature. There’s one poster here who has some experience with this problem as I recall, but I can’t remember who it is. Is it @ok4450 who has some 1980’s Subaru carb experience ? In any event, that’s what you need is to find somebody who has that type of experience. Or find a book or service manual that explains how it works.
One final idea – besides the possibility of a mistake in your recent carb rebuild — at some point a carb can become in-re-buildable. Worn out parts, bushings that leak air, etc. Maybe that has happened to yours. Maybe see if you can find a replacement carb.
Just one thing that might also help. Make sure the vacuum advance is working. It may be stuck. Apply vacuum and make sure the stuff under the distributor cap moves. I had an 87 Mazda which did not have your problem. It did have a stuck vacuum advance. Make sure the EGR valve isn’t stuck open a bit.
I’m back. Still haven’t figured much out but it has gotten much worse.
It now starts very hard hot or cold. It doesn’t fire at all for the first 30 seconds of cranking, even if it’s hot and I shut it off for 2 seconds. It still runs great once it finally starts and warms up.
I’ve verified all the linkages are moving freely. The choke and pull off are working just like Tester described. I can pump as much fuel as I want through the accelerator pump, so I don’t think it’s a carb or fuel delivery problem.
I double checked for a vacuum leak with smoke, propane, and carb cleaner and am confident there is no leak.
The timing advance is controlled by the ecu.
I also blocked off the egr valve for now just to rule it out.
Any ideas where to look next?
I’m wondering if you don’t have an ignitor problem.
For a replacement vehicle ? 
What shape are the spark plugs in? And what brand are they?
Ngk plugs about 3 months old. I’ll pull them and see if they look abnormal. I’ll also check for spark while I’m at it.
The car is in really good shape otherwise and is too much fun to give up on.