Setting choke on 4Y

[alexth]

Hi all. I have a 88 Hilux 4x4 DC with an original 2.2. 4Y motor. I have had endless trouble with idling, starting etc. Anyway, I now have an electronic distributor which seems to have helped quite a lot. However, my choke is set so that on start up, the motor goes to about 2000rpm. This is surely not necessary. Originally, my hilux started first time every time at about 1000rpm then settled quickly to around 700rpm. I need to set the choke down to 1000rpm. Can anyone tell me how to do this please?

[JohanM]

Alex,

When I had my 4Y the choke on mine was set to be running at 1500 rpm when cold and then it gradually dropped as the temperature increased. 1000 rpm is a bit low as when the choke opens up and the motor in not yet at full operating temperature the idling can drop to low causing the engine to stall at a inconvenient time.

Set it to be at 1500 rpm cold start with the choke flap fully closed. That will help the engine reach operating temp quickly and smoothly.

[Tim86]

Alex you will most likely be looking for something called a 'Fast Idle Adjusting Screw' (I am not familiar with the 4Y carb, only the 22R's). This screw limits the idle speed when the choke is operating. An example of this is on page FU23 of Chapter 6 of the 22R manual available here: https://www.hilux4x4.co.za/manual/

Unfortunately there isn't a manual easily available for the 4Y, fortunately I believe the carb has a lot simpler of a warm up procedure than the 22R's which is riddled with complicated step down cams etc.

Hopefully another member can confirm this.

[Mud Dog]

On the side of the carb (I think it faces the cab) is a circular black choke controller with a wire attached to it. You will notice that it's held in place with a circular metal flange that has 3 screws.

Setting it up is a two part procedure - start with the motor cold - you loosen the 3 screws enough so that you can rotate the controller unit and with the intake pipe removed you will see the choke butterfly at the top of the carb barrels. Rotate the controller so that the butterfly not quite fully closed, but just starting to open. Nip up the screws so that it cannot move and start the motor. Once warmed up check that the choke butterfly is fully open.

If it has not fully opened the controller is weak and should be replaced. You might be able to get away without replacement if not fully open but almost fully open when warmed up .... in that case loosen the screws again and rotate the controller to the point that the butterfly reaches the fully open position. Bear in mind that this adjustment will affect the cold start position of the choke and the only way to see if it's going to be OK is to check what it does at a cold start.

Be sure to secure the 3 screws and replace the inlet pipe after you're done.

[Mud Dog]

P.S.

If it still revs too high on cold start with the choke, adjust the controller when cold so that the butterfly is about only 5mm open. Once you test it and it still revs too high, you can adjust the choke in small increments to be a little more open when cold. Tedious, but if you have a weak controller it can be worth the effort .... replacement units are not cheap.