028 AV Super WoodBoss eq - oiler problem, service manual??

[amarlow]

Hello folks,

This is my first post, and it turns out it's a long one. I've been a member here for a while, but just lurking, reading, learning.

Now I find I am in need of help... and HOPEFULLY a couple of service manuals. I was looking for the infamous "beg for manuals" thread with the hundreds of pages, intending to search or post there... but I cannot figure out how to look for a specific thread. So... I'm here. If this is not the correct place to post the manual request, please point me in the right direction.

I own a number of saws, two of them Stihl, and both of these are having oiler problems. The saws are:
(from badge plate on top cover) STIHL 028 AV SUPER WOOD BOSS electronic quickstop, s/n 217675709
(from barcode sticker at front of saw) STIHL MS 192T, s/n 265172439

Both are currently in some state of disassembly. The MS192T has been in a box for a few months; bar oil leaking everywhere if sitting upright, but just no time to work on it recently. Since the 028 has been happy and reliable, I haven't missed the 192 so much (except when limbing and such).

I use the 028 a lot, for felling and firewood. However, the 028 has developed its own oiler problem (no oil gets to the bar -- new clean bar, sharp chain, all the obvious stuff), so I have working my way down to the oil pump and just now removed it.

The pump seems like it should be (mostly) OK -- no slop, pin is not loose, pump piston and worm gear teeth are a bit worn but not horrible. The plastic plug on the end of the pump body is VERY loose, ie. useless unless I don't understand it's use (this may be my entire problem) . The gasket behind the pump body is brittle and torn, but stuck to the machine down in its recess, and I am not sure how to get it off (suggestions?).



I cannot figure out what to do next. How does the oil get to the pump from the tank? I assume a path back behind the gasket. Same question for getting oil from pump up to the bar? But I am not sure how to get back in there to look & clean.

Any suggestions / advice would be much appreciated. And I could especially use the correct service manual for this saw. If I am also able to get one for the MS192T as well, then I'll be giddy.

Thank y'all in advance for the help.

~Allen

 

[pioneerguy600]

Welcome to the site. I will leave your thread up on chainsaw forum and give you the link below to the beg for manuals thread, it is located in the Stickies section found at the top of the page.


http://www.arboristsite.com/community/threads/the-beg-for-manuals-thread.68615/

 

[amarlow]

Thank you, PioneerGuy. Is there a better forum for me to use for the 028 oil pump questions? And when I do go to the "beg" thread, am I supposed to just request the manuals directly? or might they already be uploaded & stored somewhere?
~Allen

 

[HarleyT]

Here is your pic, and a pic of the ipls.
Was the pin in your pump, or missing?

 

[pioneerguy600]

Thank you, PioneerGuy. Is there a better forum for me to use for the 028 oil pump questions? And when I do go to the "beg" thread, am I supposed to just request the manuals directly? or might they already be uploaded & stored somewhere?
~Allen

I see Harley got back to you before I got back to this site. For the request for a manual just ask for it and one of the members will forward it to you. Your questions about the saw and its oiler belong in here.

 

[amarlow]

Back home...

Yes, Harley, the pin was present and tight, no slop. Note: when I am holding the assembled pump in my hand (out of the saw), rotating the worm gear sprocket indeed turns the piston as it should.

So now... if the loose plug in the end of the pump body (part #13 in the right side page of Harley's image) should be snug and tight and not leaking, what sort of adhesive should I use to glue/cement the plug in its hole (assuming I have nice, chemically clean surfaces, of course) ? I don't want to impede smooth rotation of the piston, but I believe this plug should actually plug the hole.

~Allen

 

[HarleyT]

The plug part# 1118 647 7000 is still available for $2.49 from the Stihl dealer.

 

[amarlow]

I'm on the way. Woot!
Still have this question: does the plug require glue/cement of some sort to keep it in place?

 

[a. palmer jr.]

I doubt that little plug is your problem, some of them just have a piece of foam in there to keep out the dirt. Take the oil cap off and drain the oil and look in there with a flashlight and you'll see how the oil gets to the pump, should be an oil line and filter in there. Most of the problems I've had with the 028 are the gears being worn out and not making good contact with each other..

 

[pioneerguy600]

I'm on the way. Woot!
Still have this question: does the plug require glue/cement of some sort to keep it in place?

I have not seen glue used, they just snap in when new, light interference fit if you like.

 

[pioneerguy600]

I doubt that little plug is your problem, some of them just have a piece of foam in there to keep out the dirt. Take the oil cap off and drain the oil and look in there with a flashlight and you'll see how the oil gets to the pump, should be an oil line and filter in there. Most of the problems I've had with the 028 are the gears being worn out and not making good contact with each other..

Pickup body/ filter can get plugged up with debris,mostly sawdust, lines break off sometimes and the end collapses. Check through the filler cap hole to see what`s in there as already mentioned.

 

[Wood Doctor]

Oh, and before you do anything, run the saw with the bar removed and the clutch cover off. Check to see if bar oil is making it through the oiler slot and dripping along the side.

 

[amarlow]

OK. I think she's fixed. First, I had to understand how the pump works. And thanks to the generosity of 'atpchas', I have the service manual now. I captured an image from the manual which is here (the text box and arrows were added by me):



The description of operation in the manual reads in part:

"The oil pump is driven by the clutch drum via two spur gears... The driven spur gear is mounted on the shaft of the single thread worm in the pump housing and drives the pump plunger at an overall reduction ratio of 1:23... The suction and delivery action of the pump plunger is effected in that it performs a vertical stroke during each revolution. This vertical stroke is brought about by a cylindrical roller in the pump housing which engages on a helical edge on the end of the pump plunger. When the plunger rotates it performs a continuous vertical stroke with a travel equal to the pitch of the helical edge.

"The pump plunger moves downwards on its intake stroke and creates a depression at the inlet port. This causes oil to be drawn into the pump housing. An oil pocket at the top of the plunger collects the oil at the intake port and transfers it to the outlet port on its upward stroke, thus compressing the oil and forcing it through the outlet port and pipe to the cutting attachment."​

This was very helpful, and in my mind pretty much guaranteed the problem was the not-sealed plug (can't create too much of a vacuum or pressure that way).

I ordered from my Stihl dealer the pump body gasket (1116-649-0600, $0.89) and pump body plug (118-647-7000, $1.49); these parts arrived yesterday. The old gasket was stuck tenaciously to the saw body down in its recessed location, and there were a few small bits on the underside of the pump body. I used a small plastic putty knife and a few careful applications of CRC Gasket Remover to scrape off the old gasket, then cleaned up both surfaces, even polished them a bit. I then blew out the oil passage from guide bar oil inlet bore to the pump outlet port; nice and clean.

This morning I reassemble everything, replaced the drained & filtered oil, and when I cranked the saw without the bar/chain (very briefly), lo and behold there was oil exiting at the guide bar inlet. Woot! I replaced the bar/chain, cranked again, and got a nice line of oil slung off the end of the bar --AND-- the original puddling leak out the bottom of the saw was gone. Woot again!

I expect the oil plunger gear and spur gear are worn enough that I should replace them soon. Ditto the chain sprocket. For now, though, I am happy. If, however, I get back to my log pile this afternoon and find I am wrong about the success of this repair, I'll fess up. Promise.

~Allen

 

[Wood Doctor]

Pssstttt.... Don't tell anyone, Allen, but I have four of these saws in my arsenal and they all run. I'll take them any day over an MS 290 clam shell.

 

[a. palmer jr.]

All my 290s have turned into 390s...

 

[amarlow]

Oh baby! I've been using the heck out of this wonderful saw the past few days. I am very happy with the repair results. Plenty of oil making its way to the chain now. I had already sharpened the chain and tuned the jets, so she's been just great.

My only complaint(?) is not all of the oil pumped makes it to the bar. Some amount of oil leaks down, either in front or behind the inner side plate. The plate isn't damaged or dented, so I'm not sure whether this is SOP.

I took time to write up the repair in hopes this helps someone else in the future. I took a few pix as I proceeded, but didn't include any with my description.

Ciao for now.
~Allen

 

[HarleyT]

Put up some pics of the bar surface, inner and outer plates, etc.

 

[amarlow]

I will do that, Harley. Thanks to you, and everyone else, for all your help with the 028 oiler problem.
~Allen

 

[amarlow]

Mr Palmer, what do you mean, "All my 290s have been turned into 390s..."?
~Allen

 

[a. palmer jr.]

Mr Palmer, what do you mean, "All my 290s have been turned into 390s..."?
~Allen

I buy them as 290s and install a 390 piston and cylinder for them. A slight muffler mod plus a little carb enrichment and you're off to the races!