Table of Contents

S83p Hijet - Carb Adjustment

Video Link - fupabox - carburetor adjustment Daihatsu Hijet S83p Japanese minitruck

From minitrucktalk forum (fupabox) (edited by JumboJimbo):

I had a bad idle in my truck (s83p) today and found a cracked vacuum line solved the problem but I also found some raw fuel in the intake bellows. Decided it was time to find out what all the screw adjustments did once and for all…

https://www.youtube.com/watch?v=fi8IoFde7Pw

There are 5 adjustments on the carb. All described as seen from the right side of the truck.

Pre

• Check vacuum lines.
• Remove intake rubber bellows to air cleaner.
• Engine cold.

1. Idle Air Bypass

Big white plastic knob on the manifold end of the carb.

• Turn it 1/2 way between stops and leave there to start.

2. Throttle Stop

Just to the left of the Idle Air Bypass Knob and at the end of the throttle cable.

• Unscrew till it just stops touching the stop and then tighten 1½ to 2 full turns.
• Leaves throttle butterfly valve open to approx. spec without carb removal to check exactly. May need to open it a tiny bit more.

3. Choke Butterfly Adjustment

Screw located on the left of the carb beside the toothed plastic wheel. When truck is cold and choke is closed this screw will adjust the maximum choke closed position.

• Screw in or out till the choke butterfly is around 2mm from fully closed.
• You can see the choke butterfly through the end where you disconnected the intake bellows.
• Now remove the short lower vacuum line from the choke actuator and either apply vacuum or suck on it ( YAH YAH insert filthy comment).
• It should slightly move the choke butterfly with suction applied.
• If not, moving remove the 3 screws on top of the diaphragm. Careful there’s a spring in there.
• Check that there are no tears in the diaphragm and the rod moves freely.
• The other vacuum line appears to be a load sensitive stepper for a/c or alternator load. It should also move (little brass valve inside top cap of diaphragm housing).

4. Fast Idle Adjustment

Smaller of the 2 screws on the right side of the carb near the alternator.

• Start truck cold and adjust fast idle speed to approx. 1800rpm

5. Idle Adjustment

Big screw on right side of carb.

• Let the truck warm up till the idle drops off the choke.
• Using the last screw, adjust idle speed to 1000rpm.

You may need to slightly tweak afterwards

I can't say whether this is 100% accurate but it worked for me.

Carb Troubleshooting

https://www.grimports.com/_files/ugd/d494d1_5c58849bbc94410c9dcb118fc9f6147b.pdf