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KS4 Idles fine but Sputters above & dies under load

Discussion in 'Subaru Sambar' started by Jason4606, Aug 24, 2010.

  1. Jason4606

    Jason4606 New Member

    KS4 Idles fine, but Sputters above idle & dies under load

    I've only had my truck for about 3 years. Always ran like a top but is tough to start in cold weather. When really cold it could take 5 or more cycles of crank-idle-die, crank-idle-die, repeat, to get it to hold idle. I just figured that was part of having an older truck with a carb. Never bothered me too much.

    Well, this spring after sitting for a while, now it will still idle after a few attempts but won't run at all under load and is rough anywhere above idle. (I ran it low on gas then mixed remainder with fuel stabilizer before storing. Then I topped off with about 3/4 tank of fresh fuel also with stabilizer this spring)

    I seafoamed carb through air intake, no better. Checked around as many vacuum lines as I could by spraying starting fluid, found no leaks.

    It will idle. But as soon as I give it gas it wants to die. Usually it will idle up as I let OFF the throttle, a noticable lag in rpm. That lag seems to get better over time. I can sit in neutral and rev it up slowly. But it sputters nearly constantly above idle. As it warmed up this morning I tried to drive it around the neighborhood a little hoping that it would work itself out.. And I ended up limping home in granny gear at idle.:eek:

    Curious now if it's crud in the carb, bad coil, fuel filter, etc... What do you think??

    I sold the truck to a friend months ago and I'm pulling my hair out to get it fixed right so he'll be happy with it. I had no idea that there were any issues when I sold it to him this spring... He's been understanding about the situation. But I need to get it right soon. Hunting season is getting close.;)

    Thanks,
    Jason
     
    Last edited: Aug 25, 2010
  2. fupabox

    fupabox Well-Known Member

    sounds like your choke is sticking closed and not opening up once warm check to see if it opens up when the truck is warm,could be a clogged coolant line into the carb or sticking linkage...could also be clogged fuel filter...
     
  3. Jason4606

    Jason4606 New Member

    The L-shaped actuator on the choke that points toward the back of the truck is fully extended to the screw spring stop. I was moving the lever toward the bellows, toward the front of the truck. I tried manually opening the butterfly valve as I applied more fuel. Never seemed to get better, just worse. Even a small motion would bog out. When I'd let it go back it would rev back up. Under idle I could open and close full range with no reaction. (Disclaimer: it was late last night and it never got really, really warm since it was finally cool out for a change. :)) But didn't notice any movement at all...

    I'll look for a replacement fuel filter that's hopefully available locally. I'm sure there are several threads on the subject.

    Good call on coolant flush. Can't hurt... Can anybody point me to an applicable flush kit and a good place to mount it? I've used the splice-in kits from Prestone that accept a standard garden hose on full-size vehicles with good luck. Just not sure if there's a good spot and hose sizes that are large enough to mount something similar?

    Thanks!
    Jason
     
  4. Jason4606

    Jason4606 New Member

    Took another look this morning... It doesn't look like the choke is pre-setting or doing anything with a tap of the gas - just stays on the screw stop. But it does start to open with some throttle after it heats up a little.

    Found another problem though. I tried the starting fluid around all fittings one more time just to make sure there weren't any vacuum leaks. And actually found that it's leaking around the throttle shaft on the left side of the carb. Can't believe I didn't notice before... See photo below:

    [​IMG]

    Is this common? Is it possible it was serviced incorrectly by previous owner and just missing a bushing? Any way to correct this on the engine, or is a remove and rebuild or replace scenario now?

    Thanks,
    Jason
     
  5. Jason4606

    Jason4606 New Member

    Started and ran Thurs but only accelerated out of idle if I pumped the gas. Eventually smelled something burning and the wires on the little actuator/solenoid above the choke were smoking. (I could re-edit picture, but too lazy today. Looks like gold 35mm film can pointing left with 2-screw thermostat style flange.)

    What is that? Now what???
     
  6. fupabox

    fupabox Well-Known Member

    fuel cut off solenoid..
     
  7. Jason4606

    Jason4606 New Member

    Thanks!

    Should I just remove the plunger and re-install? (saw this mentioned in another brand thread)

    I'd like to try popping it back in without the plunger tomorrow if so. Or is there a need to replace it, and also an internet source for buying a new one?

    Could this failing solenoid be what caused my issues, or was it collateral damage from my pumping the gas to get it to run? :confused:

    Really frustrated over getting what has been nearly a perfect little truck, back up to nearly perfect so I can deliver it to my friend. Hoping this might be a ray of light...:)

    Thanks again!
     
    Last edited: Aug 29, 2010
  8. fupabox

    fupabox Well-Known Member

    I don't have much experience with the solenoids or where to get a replacement but I can tell you they are powered with the ignition and when shut off (as they do on speed limited vehicles) then speeds are controlled to 25mph..so I assume yours is grounding out and shutting off reducing speed .There may also be a low speed solonoid as well that shuts off fuel flow when the key is turned off..either one could be the problem...wouldn't hurt to remove them and see how they work with the ignition
     
  9. Jason4606

    Jason4606 New Member

    Thks much! Will try this evening (if the rain ever stops) and post back.
     
  10. Jason4606

    Jason4606 New Member

    Gone from bad to worse.

    Now no idle. Only runs with constant revving and is extremely rough.

    I was convinced from burning smell in exhaust that it was a backpressure issue. Now after a couple bloody knuckles I have no muffler. And everything else is just as bad, only louder.

    Poured seafoam into top plate of carb, cycled throttle (engine off) enough to get 4 or 5 bowls of seafoam into carb and let it sit. Started without even a puff of smoke and barely ran just like b4. No change.

    Inside of dist cap looked fair. One contact had a decent chunk of oxidation on it. Touched them all up with embry and the rotor too.

    Pulled plugs and all were wet. (Really doubt this was still seafoam. Likely 10mins later after a bunch of trying to get it to warm up.)

    Checked spark and it was a purplish-orange thin streak. Not a thick spark or white hot. I would've thought enough to ignite. But what the heck do I know.

    Really at the end of my rope here. Still in disbelief that a perfectly running engine with no issues other than a cold natured carb has devolved into this... AND is just getting progressively worse regardless what I do.

    Going to get an aftermarket coil tomorrow and try to find a cap, rotor, plugs, wires next. But don't see that these tweaks are gonna have any significant impact.

    Guess I'll try to find a rebuilt carb to buy too. But again no idea if that has anything to do with it.

    Really losing it here. Just wanted to deliver the truck and now it's in friggin pieces.
     
  11. Jason4606

    Jason4606 New Member

    Pulled carb a few weeks back after I ordered what I thought was the service manual... Must've been up too late because I got a very expensive parts list (that I don't need) about 10 days later. So I went back and ordered the service manual. Another 1.5-2 weeks passed and finally had the service manual...

    I open it up, pumped to dive back in to my project! And...

    There's NO detailed carb info in it other than how to remove it (already figured that out) and the location of different adjustment screws! It actually says in the service manual "Detailed Instructions Included in Rebuild Kit!":mad:

    One of the main problems is that I can't find anyone that carries the carb rebuild kit. That's why I ordered the Service Manual! I was going to try to service it myself and scrounge for the individual parts as needed!:frustration: So now I have 2 expensive books that I don't need, I've wasted another month, and I've made ZERO progress.

    Does Anyone know where to get a carb rebuild kit for the Hitachi HVB32 used on KS4, a rebuilt carb, or any another carb that will bolt on and work?

    Or how about any details that have been posted about servicing a KS4 carb or one that's similar? (Seems that it's physical layout is different than most others.)

    I'm having troubles even getting some of the 15 year old parts apart. I can't even get into the bottom half of the carb to get to the majority of parts for cleaning and adjustment. Even after all of the screws have been removed it still seems hung up on something. And without more info, I hate to try to pry it apart.

    Can anybody help?
     
  12. fupabox

    fupabox Well-Known Member

  13. bowhunter

    bowhunter New Member

    Did u ever figure out what it was. Sounds like the problem I am having with my mitsu. It's hard to start when I do get it started it idles fine. Then when its under load it seems to sputter about halfway through the throttle and then seems to go away once I get the rpms up. I've checked the vac lines, put air to the supply line, changed the filter, fuel pump, cleaned carb, whacked off the cat. con, new plugs, dist. cap. I'm lost now.
     
  14. Jason4606

    Jason4606 New Member

    I think my issue was accelerator pump related. But I ran out of solutions to fully diagnose or repair the carb.

    I found a supplier that sold me a used carb that was in like new condition, and had it running like a top after about 30 minutes to install. (and a few months of frustration! ;))
     

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