Chainsaw Repair

 I got a John deere 55ev and I see it's the same as the echo 550evl.
 I have a problem with the oiler adjustment.
I'm missing parts 5 and 6 on the F diagram/page.
https://www.ereplacementparts.com/echo-cs550evl-chainsaw-parts-c-35043_35970_36802.html
I basically have the auto oiler part F7 and I think oil is pouring out of it instead of getting to the bar.
Just like what's missing in this pic:
https://www.ebay.com/itm/Echo-CS-550EVL-Chainsaw-OEM-Oil-Adjustment-Screw/321956818407?hash=item4af61f2de7:g:GXsAAOSwYaFWetHv

 You can see it with the top parts on this ebay auction:
https://www.ebay.com/itm/Echo-Chainsaw-550EVL-Crankcase/321082652103?hash=item4ac20475c7:g:r4kAAOxy9eVRMhUS

So my question is how does this work. Is just the phillips screw supposed to turn inside the brass oiler and that adjusts it?
 Or is it locked to the auto oiler and the whole brass thing turns?
 Can I loosen it and pull all the brass piece out and maybe change the o-rings?
 Or is oil coming up through the center where the missing bolt goes?
 Can I just find a new bolt and snug it down to the brass so it all turns?

Fred says =  To help the guy out, pull oil pump out.....turns counter clockwise.Clean assy & Replace all 3 O-rings (8mmx5mmx1.5mm) coat with heavy grease but try not to get into holes of the pump. Clean bar oil hole channel....compressed air backwards. Clean oil pump channel, use a feeler/plastic spray straw. Feel down thru the oil pump channel to find the crank lobe & rotated crank to find the high spot. Thread oil pump back in till it stops then back out 3/4-1 turn. This is the high oil output setting position, install item 6.....the lock at max position the item 5 to hold the lock in position. Fill tank, start & warm up saw....should have oil flow.....adjust from max to min to verify flow control. Normal setting is about half way between. Item 5&6 can be found on may saws of that series.....330evl thru 660evl. Hope this helps! If he can't find parts let me know.

 Oh, make sure filter & line for the tank are clean.

I found the limiter here:
https://northwoodsaw.com/index.php?l=product_detail&p=2614
 Found a good bolt in the small bolts can.

 I didn't pull the whole oiler and replace the o-rings.
 It was good enough to just find out how it worked, what that missing piece was for (limiter) and how to adjust it.
 Works great now.
 Thanks so much for the help.

 "I'll be back"