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Daihatsu S83P Hard Start

Discussion in 'Daihatsu Hi jet' started by Mclorivan, Dec 12, 2019.

  1. Mclorivan

    Mclorivan New Member

    I have a 1992 Daihatsu Hijet S83P, my problem is that in order to get this truck started I have to pump the accelerator about 8 times, pull up on choke listen for the attempt to start and repeat the process multiple times when the engine is almost started I then have to keep pumping accelerator to keep RPM up until it is warm enough to idle on its own. After idling for about 5-10 minutes when I finally go to put it in gear i have to keep pumping to gas to keep the RPMS high until moving. Once the truck has been gets moving it runs perfectly. Any thoughts?

    Is this a fuel solenoid issue?
    All the vacuum lines are fine.

    I have replaced the fuel filter, and fuel pump is working fine. I adjusted to carb down because it was screaming high RPMs when engine had finally warmed up. Sometimes when the engine was idling at those speeds tapping the accelerator would sometimes knock it to a dull roar but still revving at excessive RPMs
     
  2. Jigs-n-fixtures

    Jigs-n-fixtures Well-Known Member

    Your choke isn’t working right. Have you set the high idle?
     
  3. Mclorivan

    Mclorivan New Member

    Yes the high idle has been set so it is running around 1000 rpms after warming up.
     
  4. Jigs-n-fixtures

    Jigs-n-fixtures Well-Known Member

    Idle should be around 850, or 900. High idle needs to be around 1200.

    There are three adjustments you can make: idle speed, idle mixture, and high idle. There is also a choke preload, but you can’t get to it with the carb installed, unless you have dump truck, or picker/dump. Those trucks with the dump bed, have better access to the top of the engine, because you don’t have to go through the hatch in the bed. You get to the top of the engine by raising the bed, and removing the shield which protects the engine from debris when the bed is raised. You then have clear access to the top of the engine.

    You should check the best lean idle by warming the truck up, and setting the idle down to around 800, (this is to assure the main jet isn’t contributing fuel), then turning the idle mixture screw in. If the rpm drops, turn it out and see if it goes up.

    If the idle speed goes up, reset the idle to 800, and turn the mixture screw an 1/8th turn the last direction which caused it to go up, and reset to 800-rpm.

    Keep turning the mixture screw a little bit, until the rpm, stays the same or drops, and then turn the mixture screw back in the opposite direction however much you turned it the last time, and set the idle back to 900 rpm.

    Then you need to set the high idle, which should only be engaged when the choke is engaged. On most other carbs you can engage the high idle cam with the engine warm and set the high idle. On the carbs on the Hijet, the high idle cam is tied directly to the wax plug choke motor, and you can’t move the cam to set the high idle. I set mine the next day, when the engine is cold, and set it to around 1200-rpm, with the truck just started.
     
  5. Mclorivan

    Mclorivan New Member

    Thank you very much for that. I've been trying to find the correct way to adjust this carb. This I formation will get it running smoother than ever.
     
  6. Mclorivan

    Mclorivan New Member

    Just wanted to put some information out there as to what I did to get this running consistently

    1. Mechanical Fuel Pump was going bad. Replaced with Electric Fuel Pump and Regulator set at 2.5 lbs pressure

    2. Replaced Distributor cap/rotor with new plugs and wires

    3. Previous owner replaced carburetor with the newer after market one that uses manual choke. All the vacuum lines were in the wrong place but also half of them no longer were needed because of manual choke setup. After lots of trial and error vacuum line are in the best correct location.

    4. New clutch. Not a 2 hour job by the way, I read many posts on here stating that it was a easy job. Wasn't hard but was a 2-3 day job.

    5. New thermostat. Almost blew the head gasket but saved it from that demise.
    0408201007.jpg 0408201007a.jpg

    Anyone have any questions I can try to assist you or point you in a direction to look.

    Ivan McClain
    mclorivan@gmail.com
     
    Mini_hijet likes this.
  7. Jeffrey Doan

    Jeffrey Doan New Member

    I have a 91 S83P. I keep it on my 34 acre property in Western Kentucky, but I live in SE Missouri. In January, I found that the fuel return line was dry rotted and broke. I bought a fuel line, but didn't get around to fixing it until May (damn COVID-19). Then I found my fuel filter had a hole chewed into it. Damn squirrels! I replaced the filter. I was going to go fishing one afternoon when the motor stopped and wouldn't start again. No fuel in the filter? Another fuel line broke. I replaced it the next morning. After running about 2 miles it wouldn't start...again! No fuel in the filter! No obvious leaks this time. Any suggestions for what to look for next? At least it stopped on my property and not 2 miles away!
     
  8. Jigs-n-fixtures

    Jigs-n-fixtures Well-Known Member

    Since the problem you’re having thus far is the rotted fuel lines, I say put in an electric fuel pump as close to the tank as you can get it, and install a fuel pressure regulator as close to the carb as you can. Bypass the fuel pump. I left the fuel pump in place on mine. It won’t hurt anything to just be there, and it looked like it would be a royal pain in the toucus to get it out, (part of why I switched to an electric pump). With the electric pump, and a regulator, you no longer need the return line so it can be blocked off at the tank.

    Then make sure that the Vacuum lines are still good, if the rubber in the fuel lines is rotted out, it is a good bet that all the vacuum lines are at least suspect. I just replaced all of mine with 3-mm silicone lines. Seemed teh simplest thing to do, and I used yellow lines, so I could label the ends with a “Sharpy“. Which made it much easier when i had to remove and replace the carb.
     
  9. Limestone

    Limestone Well-Known Member

    Shoot the squirels
     
  10. Limestone

    Limestone Well-Known Member

    You can just roast em over an open fire! Tastes like chicken!
     
  11. Mclorivan

    Mclorivan New Member

    With the electric fuel pump and regulator you still need a return line to prevent premature failure of pump. Just put a T in the line after pump and before regulator.
     
  12. Jigs-n-fixtures

    Jigs-n-fixtures Well-Known Member

    That is dependent on the fuel pump. the one I installed automatically cuts out at 7-psi. The regulator is designed to get the pressure down to the 2.5-psi the carburetor needle and seat can handle.
     
    Mclorivan likes this.
  13. Mclorivan

    Mclorivan New Member

    I thought that too, until I found myself stuck in the woods with a dead fuel pump that was around 3 months old. A "T" in the line is a small price to pay for extra protection. But your right if you buy a fuel pump that stops pumping at too high of a pressure.
     

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