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1990 S81P 87D06 Carburetor / Rich / Flooding Issues

Discussion in 'Daihatsu Hi jet' started by neverstopbuilding, Apr 3, 2024.

  1. neverstopbuilding

    neverstopbuilding New Member

    I recently completed a bunch of maintenance on my Hijet, I list it here for context:

    Initial symptoms:
    • Over revving under load -> clutch slipping
    • Very difficult starting, black smoke, loud exhaust
    • Observed rust hole in muffler
    • Inconsistent, intermittent, or no switching to 4WD / Diff lock
    Service Performed
    • Replace clutch, pressure plate and throw out bearing
    • Adjust clutch cable
    • Top off transfer case fluid
    • Change engine oil and filter
    • Change fuel filter
    • Change air filter
    • Change spark plugs
    • Inspect, clean ignition points and rotor
    • Disassemble, clean, rebuilt carburetor using G&R kit
    • Replace numerous worn vacuum lines
    • Free up and lubricate 4WD vacuum diaphragms and linkages
    After all that the drive train is in great shape, but the car still barely starts with out lots of manual fiddling with the choke and throttle. I was able to get a consistent warm up idle, but it seems very rich and often I see a cough of gas on shut down. As of this writing I've tried:
    • Checked float and needle twice, ultimately reverting back to the stock needle seat as I noticed the original hole was smaller than the part I got with the rebuild kit.
    • Added slight bend in the float arm to make extra sure it seats. Everything in there is very clean.
    • Removed charcoal canister and ran the vent line to the frame rail hose. Plugged the vac line to the canister.
    • Several adjustments to the carb to no real avail. If I manually manipulate things to warm it up enough, it seems to settle down to a usable idle, but then if you turn it off its back to square one.
    • Fuel is flowing back to the tank, I removed the return line to verify.
    Some questions:
    1. I've not measured the fuel pressure yet, is it possible that something inside the fuel pump could be worn/stuck, thereby increasing the fuel pressure to the carb?
    2. Does anyone know the correct jet size for these carbs? I still have the old jet, I think the rebuild kit jet is the same, but I'm not sure. Although the rich start seems just the same as before the rebuild.
    3. What is the correct initial position of the plastic gear choke preload spring on the toothed armature?
    4. If I just fill the float bowl with fuel and bypass the fuel pump, that is no pressure, is that a good way to determine if its a pump issue?
    Thanks for your help, I've read probably every post about starting/fuel issues. Hoping to create the thread I wish existed for the s81.

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