MS211 oil pump seating issue

[someguy1942]

on the MS211 stihl chainsaw how can u know for sure u have the oil pump installed at the correct depth so that the its hole lines up with the hole in the housing that receives the lube? many youtube videos say to simply push the oil pump in until it won't go any further but when i did that, it clearly wasn't in the correct position given the oil pump gear wasn't properly lined up with the worm gear that drives it. i've read in various posts that stihl chainsaws have a "shoulder" that makes getting the proper depth easy but this isn't the case with this model chainsaw. please help if u know what i'm missing here. i can't imagine stihl would engineer this in a way where the pump could slip out of position from years of vibration from the work it's doing but without a "shoulder" or something, it seems the pump could do just that.

 

[HarleyT]

Here is the manual.

 

[someguy1942]

Here is the manual.

Thank u so much for the service manual. Unfortunately it says on page 70 "Use the lever (1) to press the oil pump into the bore as far as stop." The way that's worded, it implies there should be some sort of shoulder (or something) the pump bottoms out against so it's very obvious where it should be positioned. When i reinstalled the pump, it just kept going until it was so far away from the worm gear that drives it. Someone on another forum posted it was a gigantic headache to get the pump into the correct position but they never explained what they did to pull it off.

 

[Stihl-Pioneer]

When I did mine. I measured the old ones depth with verniers and installed the new one to the same depth by measuring and a little tapping until I was within a few thousands.


Sent from my iPhone using Tapatalk Pro

 

[someguy1942]

looking back, i should've taken some sort of precaution such as u describe but sadly i have to follow the other lead now, assuming there is this mysterious "stop" that will take the thinking out of the work. When i was tapping it into position, i kept waiting for it to "bottom out" but at some point it was obvious it was past the point where its gear would line up nicely with the worm gear that drives it. What exactly stops the pump from going beyond a specific depth? from looking at both parts, the pump nor the hole it goes in seems to have any "shoulder" or anything that would prevent it from being pushed all the way thru....i must be missing something.

 

[HarleyT]

I think that they mean it stops when the approved tool bottoms out. The best you can do is line the channel/passages up correctly, then press it down until it shows a certain depth from the edge of the white plastic to the edge of the pump.
There have been threads about doing this on 025/ms250, and maybe on the ms171, and that depth was given, so you might do a search here.

 

[someguy1942]

looking back, i should've taken some sort of precaution such as u describe but sadly i have to follow the other lead now, assuming there is this mysterious "stop" that will take the thinking out of the work. When i was tapping it into position, i kept waiting for it to "bottom out" but at some point it was obvious it was past the point where its gear would line up nicely with the worm gear that drives it. What exactly stops the pump from going beyond a specific depth? from looking at both parts, the pump nor the hole it goes in seems to have any "shoulder" or anything that would prevent it from being pushed all the way thru....i must be missing something.

today i'll try another approach which u made me think of. if your assumption is correct then there's nothing preventing this pump from vibrating out of position slightly after many many years of extreme revving. that makes me wonder if that's what caused my original problem of slowly getting less and less lube to the bar until it stopped completely.

 

[someguy1942]

SOLVED: so for anyone reading this post down the road, i wanted to tell u what happened so maybe it would provide u with a clue. the local chainsaw repair "pro" got my chainsaw oil lube flowing again - all he did was take the oil cap off and put it on its side for 20 mins. said it was "air locked" which i guess happens when u take it all apart to figure out why it wasn't oiling the bar/chain in the 1st place. sounds like i fixed the original problem but in doing so, created this odd secondary "air lock" problem that none of the youtubers nor anyone online mentioned could happen when u introduce air into the oil's pathway. i'm a little confused why this wouldn't happen anytime u're out cutting wood and run out of oil in your reserve tank. maybe someone can explain that.....

 

[HarleyT]

Sorry, I assumed that you were trying to put in a new pump, I didn't read it very close.

 

[someguy1942]

i was trying to get the pump back into position as a subtask of the bigger issue

 

[Patrick1903]

i was trying to get the pump back into position as a subtask of the bigger issue

A lot of really good oil pump measurement info on these saws at this thread:

Thread 'Stihl "Plastic" Saw - Oil Pump Removal & Installation'
https://www.arboristsite.com/threads/stihl-plastic-saw-oil-pump-removal-installation.300051/

Glad you got your line purged of air and saw is oiling again.

 

[stihltech]

Air lock on oil tank? Does the vent work? Is the passage on the pump clean and lined up? Does the pickup hose seal correctly to the oil pump passage? These are the tings we look for in the shop.