1990 Subaru Justy mk1 running problems - carb help thread

[Station]

Hi!

I bought my Justy a few months ago, it's a nice car, but runs like absolute rubbish.

Terrible to start in the morning (even worse on cold mornings), doesn't idle when cold, and typical carb troubles.

All the vacuum pipes are OK, I have no idea about carbs, and generally avoid any car with them as they've always been trouble.

 

Does anyone have any experience with these - they're Hitachi.

 

http://subarujusty.proboards.com/thread/2257

 

It's autochoke (think running off vacuum). I chucked some Redex into it and left it a week and while runs better, it seems to have gotten worse overall (though I don't think it's anything down to the Redex as it's been gradually getting worse). It also sounds like the engine is about to chuck all three pistons, valves, springs, conrods, etc etc out through the exhaust (which sounds like it's blowing, but it isn't). The engine's done 145,000 miles which is probably very high for a 1.2 3 cylinder.

It's a very good car otherwise, and has been looked after very well - and the purpose I bought it was to see off the winter with 4WD, but I'm going to be lucky if it even sees the winter the way it's going. You can swap the head for a fuel injection one on these, which I'd do instantly if I could find one.

 

HAve to drive it down to work tonight, and hopefully book it into a garage to get sorted, if anyone will touch carbs nowadays?

[Jim Bell]

http://subarujusty.proboards.com/thread/3896

 

 

though youve probably already seen this thread.

[overrun]

Without getting into the specifics of different types of carb, I reckon you can't go wrong with a strip and clean 9the carb loooool0.

 

This also gives you opportunity to inspect the diaphragm etc.

 

I had a B19 Volvo that gave many running problems. Turns out the carb was full of old, gummed up fuel.

[KruJoe]

Correct.

That Samara was running* increasingly badly, a strip-down revealed a perforated diaphragm.

[hauserplenty]

Check to see if the the heatstove is in place--there should be a flexible aluminum tube on bottom the air cleaner intake which diverts hot air from the exhaust manifold into the carb throat. There should also be a vacuum line connected to a butterfly valve on the front of the air cleaner. As the engine warms up, the butterfly valve should open to the outside air, admitting less of the heated air. Without either of these items, even a properly adjusted new or rebuilt carb will give trouble with cold starts. You've likely got a problem with the choke adjustment as well. One way to check for this is to remove the air cleaner after it's been sitting overnight, then try pushing the pedal all the way to the floor ONCE. Do so slowly, as this will*:

1.  Set the choke to the closed position

2.  Engage the fast idle cam, which has three steps (fast, medium, slow)

3.  Squirt fuel down the intake ports. The accelerator pump works on the same principle as a spray bottle, so a quick stab gives less dead dinosaur juice than would a slower, more deliberate motion.

Then: crank it. If it starts, but runs rough, try manually closing the choke to see if it seadies out. If you put your hand over the carb throat and it doesn't even stumble (after it warms up) then you could have a vacuum leak. Make sure the bolts are tight around the carb, as they often work loose over time and create vacuum leaks which are enough to affect cold starts. If so, a new carb gasket is in order...at a minimum.

You can also look down the carb throat with a mirror (engine OFF 'natch, cobba) and pull the throttle back. The fuel should spray. If it is dripping instead, it is not vaporizing, and will not burn well when the air is cold.

 

*Should. If the choke doen't close, or the throttle lever does not move, by all means find a specialist or just order a new carb. Rebuilding the old one is a bit more advisable, since they don't make 'em like they used to. I've had terrible luck with carbueretors, and those were purchased several years ago. I can't imagine quality control has improved much since then.

Also check the timing and the distributor diaphragm(s). If those are not getting the proper vacuum signals they could also contribute to cold starting problems even with a new carb.

 

Reassembly is the reverse of removal etc.

[Station]

Will try a strip down this weekend. I've got the complete workshop manual.

Considering the Weber setup, has to be a million times better than these hitachi/solex carbs that come on jap cars. Worst thing is fuel starvation round corners though.

[willswitchengage]

^^Dunno about what's happened since (I sold this as I was fed up of the crap carb) but I found one depression of the RH pedal and the car started fine, regardless of temperature, even when the carb was exhibiting all of what Station says. It's only when I drove off, and touched the accelerator again, it would engage spazmodism and fail to idle properly. Never suffered any problems in corners/driving under any load, though.

[Station]

Yeah, you have to depress the pedal to start it - it seems to have gotten worse, and is not very pleasant in the first ten minutes, and now it won't idle. Such is the nature of carbs. If it was FI it would be perfect, I otherwise love the car.

 

Does anyone know of where to get carb rebuild kits? Or any decent carb tuners in the north west/west midlands?

[willswitchengage]

Donor?

 

http://www.gumtree.com/p/cars-vans-motorbikes/1991-subaru-justy-12-gl-4wd-mot-june-2014/1039124122#photo-content

[Minimad5]

Does anyone know of where to get carb rebuild kits? Or any decent carb tuners in the north west/west midlands?

Dave you big wimp !

Ebay could be the best source for rebuild kit, and we'll clean it out in my unit sink (Using some dETROL)

how does that sound ?

[Lacquer Peel]

Isn't it some weird Hitachi carburettor?

[Lacquer Peel]

Aye - here's a repair kit from dugong's favorite(sic) country.

 

http://www.ebay.co.uk/itm/Carburetor-Fuel-System-Repair-Kit-Hitachi-DFC328-Subaru-1-2L-87-88-89-90-91-92-/231015164213