Makita 6421 not oiling

[Need2Saw]

First thread here, looking for some help.
I purchased a 6421 and cannot get it to oil.
Cleaned around pump and pump drive.
Checked the pump gear, it spins freely.
Flushed tank and strainer is clean.
Tank vent is clear and operational
Filled oil tank with gas and ran saw, it would move gas through the pump and run out the oiler hole. Filled tank with bar oil and ran saw. It barely spits oil out sporadically.
One thing that seems off to me is the oil pump adjuster. It turns maybe 1/4 turn with no clicks or divots in the adjustment range. I have it turned counter clockwise with the nipple pointing to the clutch side.
What do I check next? Thanks

 

[Deleted member 149229]

@CJ Brown or @fordf150

 

[Need2Saw]

I took the oil pump off and removed the internal parts, there is still a nipple on the plastic adjuster screw but it looks slightly rounded. I'm not sure how worn it it. I cleaned out the pump and passages; ensured the oil lines are clear and put it all back together. It is oiling better now but doesn't seem to be enough. I will get cutting with it to see.

 

[Need2Saw]

My next question is, how does the oiler work? Does the flat spot create enough centrifugal force to pump the oil? It seems that the shaft in the pump moves up and down as it rotates. If you turn the adjusted counter clockwise to get more oil, does the shaft goes further up or down?

 

[Sepia]

I will start off by saying I have never worked on a 6421, so I can't be much help. On the pumps I have had apart, the pump shaft has a ramp on the end of it that rides on a pin as it rotates. This causes the shaft to move in a linear motion similar to a valve following a camshaft. This is the pumping action that moves oil from the tank to the bar/chain. The adjuster limits the range of linear motion of the pump shaft. More range = more oil pumped.

 

[Need2Saw]

I will start off by saying I have never worked on a 6421, so I can't be much help. On the pumps I have had apart, the pump shaft has a ramp on the end of it that rides on a pin as it rotates. This causes the shaft to move in a linear motion similar to a valve following a camshaft. This is the pumping action that moves oil from the tank to the bar/chain. The adjuster limits the range of linear motion of the pump shaft. More range = more oil pumped.

Thank you for that explanation.

After trying a few things tonight, it is oiling.
The last thing I did was turn the adjustment screw and pressed it in until the spring was fully compressed. When I released pressure, it sprung back out to normal position. Maybe I didn't have the adjustment screw in far enough or the o-ring seated properly? I don't know exactly what this did, but it's oiling a 20" bar great at the moment.

 

[Need2Saw]

Used almost 1 tank last night cutting up firewood, oiling good at this point.