Farmall 706 d282 injection pump automatic advance circuit

I am in a confused state right now and need help. My 1966 706 with the d282 has the automatic advance circuit on the bottom of the injection pump. I have studied it, and how it works, higher rpm's
higher pump pressure pushes on a spring with a ball on the end of it, then to a power piston unit, pushing it out. while the opposite side of it, there is another piston but has an advance spring
behind it. that spring must push the piston out at idle, to advance the injection timing... ANYWAYS, there is an adjustment for the unit, and i am turning the screw clockwise. after i did that, the
tractor actually ran better at high rpm's, there was hardly any popping or poofing. before i adjusted it, it was pretty bad. the diagram i am looking at doesn't show the adjustment screw. I'm not sure
why. my main question here is, I want to know exactly if the advancement of injection BeforeTDC increases or decreases when i adjust this screw and lock nut in CLOCK wise. see, i adjusted it in
clockwise a few turns while the motor was running at 2000 rpm. and a lot of poping and fluttering went away, it really cleared it up. thank you for any help acquired.
P.S. the reference for the diagram is on page 29 of this link http://www.stanadyne.com/dealerportal/ssi/english/Product%20Manual/99523.pdf
 
Here is an picture of a exact pump. the screw adjustment I'm talking about is on the very very bottom if the pump. its covered by a safety tamper proof cap
a149694.jpg
 
Yes, turning the screw in on that particular pump will start the advance to begin at a lower engine speed. Some IH tractors used shims on the spring side piston to adjust it correctly on the test bench. The screw was set out .750 inch and left there, then shims added or removed as needed to get the advance curve versus pump speed set. The 460, 560, and 660 pumps used load advance while the 706 used speed advance. There's also a chance the advance was working correctly, but the static timing is late.
 
Thanks, it makes sense now. Your right, I think the static timing does need to be adjusted, I'm just trying to figure out though..
SO,
everything below is stated with motor having no load.

With the screw never adjusted before, it runs pretty smooth at idle with few flutters, but runs terrible at high rpm's (2000rpm) fluttery, poppy, blue smoke, and stuff.

AFTER i adjust the screw 3 to 4 times clockwise inwards, it runs same at idle speed but has a slight knock, but runs VERY smooth at 2000 rpm with no knocking at all.

from these conclusions, I'm just confused wether I should advance or retard the static timing. what is your opinion?
 
Okay, thank you. I will adjust that when i get home today. I will let you know how everything goes and what happens after i adjust it.
 
You need to put a window on so you can watch the advance. It should start to advance at about 1000 rpm and be full advance at or before 2100 rpm. Fuel pressure controls the advance so any thing that cause low fuel pressure will affect the advance. Usually I it is worn blades in primary pump causing low pressure, not always though. If you change static timing to correct the misfiring, you will cause other problems. One or two degrees change from static specs you can get by with but some will just pull pump toward them until it runs better, not good.
On the test bench they use a more sophisticated method of checking the advance, but on the tractor a window works just fine. On that picture of a pump I see the bypass system is still intact and that should be thrown away when ever a pump is serviced. Not saying that is your pump or even a recent picture.
 
Okay, so, wait, i just had a brain explosion. inside the automatic advance device on the bottom of the pump, there is a Advance spring... That advance spring piston pushes all the way out when there is absolute no pump pressure, That means the injection timing has been completely retarded? if so, wouldn't the motor start harder? When the motor is idling, that means the pressure would slightly push the power piston against the advance spring, advancing it, correct? when motor is wide open, the power piston should be fully extended against the advance spring, meaning it is fully advanced right? and when its fully advanced, the injection is occurring even EARLIER than top dead center right? if this is all correct, then Ill be completely understood.
 

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