Stihl 08s rebuild

[daedna]

I am new to this site, but it seems as though y'all might be able to help me. I am rebuilding an Stihl 08s and have the following questions:

1. When I spray gas/oil into the cylinder through the spark plug hole, I can get it to fire. Otherwise it will not start or even fire. I rebuilt the carb and blew out the fuel lines...still does the same thing.

2. I'm not sure it is all original. Sprocket cover says "08s" but according to acresinternet.com, the "08s" has an interlock and hand guard...mine does not.

3. Flywheel has 2 broken fins....exactly opposite each other. Maybe one broke and the previous owner broke off the opposite one to keep it balanced???

Thanks for your responses...I really don't want to replace anymore than I have to!!

 

[leeha]

It sounds like your not getting any fuel.
If you did the carb correctly then you might
have a cracked fuel line, plugged fuel filter,
and possibly bad crank seal. What carb is on it?
Is there a pulse line? if so it might be bad as well.
Just a few thoughts.


Lee

 

[pioneerguy600]

I had an exasperated fellow bring in one recently that was doing the same thing. After doing a little checking I dumped out the gastank, there was no pickup line, it had rotted off and was actually a lump of goo in the bottom of the tank. A new line and filter got it going again.
Pioneerguy600

 

[buzz sawyer]

If you have a Tillotson HL carb, as I suspect you do, did you change the inlet needle and seat? I've had problems with them sticking shut.

Older 08s did not have the hand guard - mine doesn't.

If it were mine, I'd prefer to replace the flywheel to eliminate the out-of-balance question, but unless you intend to run it a lot, it may not hurt anything the way it is. Picture may help.

 

[daedna]

Thanks for the help...it was the fuel filter. I work at Stihl..but we never deal with used saws. I didn't think the fuel filter could get so clogged that it would block the fuel flow completely.

I attached a picture of the flywheel.

 

[7oaks]

Welcome to the site...Looks like you got the help you needed real fast. Great group of guys here!

 

[pioneerguy600]

Thanks for the help...it was the fuel filter. I work at Stihl..but we never deal with used saws. I didn't think the fuel filter could get so clogged that it would block the fuel flow completely.

I attached a picture of the flywheel.

You could run that saw just the way it is, those chipped off fins won`t even be noticed. I have seen much worse and the saws ran for years without problems, actually some of them are still running 20-30 years later.
Pioneerguy600

 

[blsnelling]

You could run that saw just the way it is, those chipped off fins won`t even be noticed. I have seen much worse and the saws ran for years without problems, actually some of them are still running 20-30 years later.
Pioneerguy600

+1. Plus they're nearly 180° opposed, balancing each other out. It's a non-issue IMHO. These things don't turn high RPMs anyway.

Did you have the cylinder off the saw? Perhaps the impulse passage is blocked. Make your own gasket? How about the impulse passage on the intake and carb gaskets?

 

[daedna]

OK...couple more questions while I wait for the repair manual to arrive.

1. The saw runs and will idle and reach high speed. However, sometimes I can keep it at high speed for minutes at a time w/o problems...sometimes the rpm's drop and it starts backfiring.

2. Should I be using 20 to 1 mix as stated at acresinternet.com??


Carb was rebuilt
fuel filter replaced
fuel lines blown out
impulse passage in carb spacer was cleared
saw responds to H & L carb adjustments

Thanks again!!

 

[JasonBmac]

1. I'd expect that to be ignition related.... Check the plug wire, boot and plug first.... then check "further"....

2. Use your preferred mix. Oil technology has advanced alot more than 2 cycle engine tech. As long as your mix is more oil rich than the leanest recommended on the bottle, it will provide adequate protection... I personally wouldn't go much leaner than 40:1, but that's just me... Only on 2 cycles with plain bearing rods (rather than roller/needle setups) is a grossly rich oil ratio needed... And you won't find that on a saw unless it's a real dinosaur....

Good luck!

J

 

[pioneerguy600]

OK...couple more questions while I wait for the repair manual to arrive.

1. The saw runs and will idle and reach high speed. However, sometimes I can keep it at high speed for minutes at a time w/o problems...sometimes the rpm's drop and it starts backfiring.

2. Should I be using 20 to 1 mix as stated at acresinternet.com??


Carb was rebuilt
fuel filter replaced
fuel lines blown out
impulse passage in carb spacer was cleared
saw responds to H & L carb adjustments

Thanks again!!

Your mix would not be causing the saw to backfire. I run 50 odd vintage saws on 40:1 mix and they all run fine on it. Backfiring is usually a timing problem or a module starting to go bad. On the older saws with points the gap could get off enough to cause slight backfiring, I think your 08s would have an electronic module, check the gap between the module and flywheel, it should be .010-.012.
Pioneerguy600

 

[djmercer1]

OK...couple more questions while I wait for the repair manual to arrive.

1. The saw runs and will idle and reach high speed. However, sometimes I can keep it at high speed for minutes at a time w/o problems...sometimes the rpm's drop and it starts backfiring.

2. Should I be using 20 to 1 mix as stated at acresinternet.com??


Carb was rebuilt
fuel filter replaced
fuel lines blown out
impulse passage in carb spacer was cleared
saw responds to H & L carb adjustments

Thanks again!!

do you have a service manual, id be grateful for a copy of it if you do? if you only have a paper copy, i would make a electronci copy for passing around if you want to wokr with me.....

also as brad said, the broken fins shouldnt be an issue considering how their placed, the balance on those flywheels isnt perfect anyway, but if your concerned you could always file the broken edges until even by eye...

 

[djmercer1]

1. I'd expect that to be ignition related.... Check the plug wire, boot and plug first.... then check "further"....

2. Use your preferred mix. Oil technology has advanced alot more than 2 cycle engine tech. As long as your mix is more oil rich than the leanest recommended on the bottle, it will provide adequate protection... I personally wouldn't go much leaner than 40:1, but that's just me... Only on 2 cycles with plain bearing rods (rather than roller/needle setups) is a grossly rich oil ratio needed... And you won't find that on a saw unless it's a real dinosaur....

Good luck!

J

as for being ignition related, the routing of the coil wire lends itself to being pinched and getting memory effect from being formed by being bent for a long time with heat.... when unbent it can then crack the insulators and cause arcing as current builds up under heavy throttle...

 

[garyss]

I am such a nut! I would take my dremel and even off the broken fins so that they are as exactly the same as you can make them
That is not as good as not broken fins

but pretty good


gary

 

[buzz sawyer]

Backfire

You may have points on that model. Assuming you do and the gap is too small, (effectively advancing the timing) you could get arcing and firing at the wrong time causing the backfire.

 

[daedna]

do you have a service manual, id be grateful for a copy of it if you do? if you only have a paper copy, i would make a electronci copy for passing around if you want to wokr with me.....

also as brad said, the broken fins shouldnt be an issue considering how their placed, the balance on those flywheels isnt perfect anyway, but if your concerned you could always file the broken edges until even by eye...

I have received the service manual. I only have it as a paper copy...however I could try to scan it and e-mail it to you. Original copy's are available on e-bay too...I got mine used for $10, but most are new for $20+shipping.

If you would like a copy...send me a request at [email protected].

I know I can scan it...but it may require several emails to send due to size (24pages)...

Dave

 

[bonden]

This is the 08s i have ,i will order me some new parts to get it running some day ,the fuel is cumming out where the cases are fitted to gether but it run with fuel pored throe the carburettor.This saw does not have handguard, so maybe they diddent have on al models.

 

[daedna]

Here is a picture of the 08s I'm rebuilding. I think yours is a bit older because of the Stihl logo. The hand guard and trigger interlock must have been optional equipment back then. Good Luck with yours!

 

[Ogorir]

Here is a picture of the 08s I'm rebuilding. I think yours is a bit older because of the Stihl logo. The hand guard and trigger interlock must have been optional equipment back then. Good Luck with yours!

Hi, just joined here.

My boss has a bunch of 08s/510s that I'm going through when I have time. I just bought a fleabay manual (should be here next week) and I plan on cutting it up and doing high-quality scans and posting the PDF somewhere. I figured I'd throw a post up here as I found this site looking for a manual for these.

 

[Yukon Stihl]

Hi, just joined here.

My boss has a bunch of 08s/510s that I'm going through when I have time. I just bought a fleabay manual (should be here next week) and I plan on cutting it up and doing high-quality scans and posting the PDF somewhere. I figured I'd throw a post up here as I found this site looking for a manual for these.

Hi
Any chance that you may have some parts available?
I need a clutch cover/oiler/handle assembally for one i have in a box waiting for a rainy day.
Thanks Thomas