External Air/Fuel Idel Adjustment

[Mhastings]

I have been trying to adjust the air/fuel adjustment valve on the back of the injector body it does not seem to want to turn CCW OR CW what could the issue be? Can it be repaired short of a complete rebuild?

[garymand]

The adjust ment screw that sticks out the back of the FIP is gas only.  cw is more gas at idle.  It is not really the adjustment screw.  The real adjustment screw is inside.  This screw is just a link to engage the real screw.  You have to push the outside screw in by about 3 or 4 mm (1/4in) and find the screw slot to engage the internal screw.

It is a 3 step process: 1) push the screw in
2) find the and engage mthe internal slot.
3) turn the internal screw some number of clicks.

[Basil]

@Garymand.
Please tell Mhastings to stop the engine before step 1

[garymand]

Sorry, I don't think about that anymore.  It has become part of my 'common sense.'     Hmm, maybe that's what happened to the O-ring in  the parallel thread that was broken in half and missing part.  Jaming the screw all the way back just might do that.

"Wise men learn from other's mistakes.  Smart men learn from their own."

[ja17]

Hello mhastings,

Make sure the engine linkages are correct first. Do "The Llinkage Tour".  These injection systems "wear" rich with age.  But you need to find out if when your system is running rich. Cold, hot, at idle, mid range, high range,at acceleration  or all of the above? Read about "The Split Linkage Test" to help determine if your system and when your system is running rich.

Yes, the thumb screw on the back of the injection pump is for low range fuel adjustment (idle and up to 1700rpms). It must only be adjusted when the engine is off and it is engaged by pushing in on the knob, engaging the slot and turning. It will "click" as it turns. The idle air adjustment is the large slotted screw on the intake manifold. Spend some time searching up the information on these items on this site. Once you determine what is going on, we can help you adjust the injection correctly.

The Pagoda Golden Rule..........  "Before altering the expensive and complex injection system, make sure you have a perfectly tuned engine, a tested WRD, a leak proof starting valve, correct engine linkage, and a clean fuel supply with adequate pressure and volume".