Chainsaw Repair

My wife bought me this 5000 for Christmas 40 years ago. It ran great for 15 years but started having trouble so I got a 346XP, then a Redmax 353. I love all these saws and would like to keep them all running. The 5000 cuts well except that I can't get the oiler to pump up to the port for the bar. I put a pump on it many years back and the worm gear and splines look ok. I just put a new inner bar plate on but have never replaced the oil lines. I have a used upper one on order(parts aren't easy to find!). The lower one doesn't have anything obviously wrong unless there's a filter or check valve thats supposed to go in the coil spring on the bottom. I'm sure it's brittle though.

It must be pumping because oil drools out the bottom of the bar plate. The upper hose looks like it may have broken off where it necks down. I'll replace it when the other one gets here.

I'm confused about the little pin (.050"-.060") that goes into the case along the pump cylinder. I had replaced it with a cotter pin though I can't remember doing it.
What the heck does it do and what dimensions should a replacement be?

I have a hard copy service manual but dont think I have one in pdf.  @ray benson might have one he can send ya.

Worked on them alot and replaced alot of oilers on them. But dang if I can recall anything.

Think only thing I have left is that 490 crankcase and the sign in them now.

My wife bought me this 5000 for Christmas 40 years ago. It ran great for 15 years but started having trouble so I got a 346XP, then a Redmax 353. I love all these saws and would like to keep them all running. The 5000 cuts well except that I can't get the oiler to pump up to the port for the bar. I put a pump on it many years back and the worm gear and splines look ok. I just put a new inner bar plate on but have never replaced the oil lines. I have a used upper one on order(parts aren't easy to find!). The lower one doesn't have anything obviously wrong unless there's a filter or check valve thats supposed to go in the coil spring on the bottom. I'm sure it's brittle though.

It must be pumping because oil drools out the bottom of the bar plate. The upper hose looks like it may have broken off where it necks down. I'll replace it when the other one gets here.

I'm confused about the little pin (.050"-.060") that goes into the case along the pump cylinder. I had replaced it with a cotter pin though I can't remember doing it.
What the heck does it do and what dimensions should a replacement be?

Link is for the Partner 5000 service manual.
https://www.mediafire.com/file/7mtqgowjmsqpsgq/5000_sm.pdf/file

If looking for new, check IPL for poulan pro 325 aka partner 5500 (cant recall if they were the same oiler set up) and see if parts in stock ay ereplacementparts or ordertree etc.   505310745 503101601

How I was getting new parts for my 500 5000 490 590 etc saws for a while.

PP325 IPL  http://www.barrettsmallengine.com/partslist/poulanpropp325chainsaw.pdf

I was thumbing through what bit of Partner stuff I have and have not down loaded that link .However an old trick sometimes you can flush the oiling system with a tank full of kerosene or diesel fuel  .I've done this on nearly every type of oiling systems from Stihl, McCulloch and recently on two PartnerP-100's I completely restored /rebuilt .
Just fill the tank and let it sit a day or so then fire it up and let it idle .A lot of times it will cure whatever ails it .