Stihl MS025 Impulse Line Replacement.

[neoborn]

Hey Guys,

I have an MS025. The saw was sold to me for $150. Good saw but didn't really know much at all when I first got it. Turns out it had / has some minor issues.

Issues
* Air Filter One Side Clip Broken - This, I believe led to the secondary problem.
* Bogging Down - Saw would run well for a while then bog down and die.
* Sprocket Bearing - On attempting to service this saw found bearing was completely missing

Purchased
* New Fuel Line - recommended as a first line of troubleshooting by the good folks here.
* New Impulse Line - As above
* Carb Kit
* Sprocket Bearing (crankshaft bearing?)

I don't really know the lingo or wordsies of what's what but, I was having some issues. First the air filter had one of the clips broken off. I didn't notice this right away. After a while then the saw was fine for a bit then started bogging down in the cut, took saw off logs, would apply full throttle and I would accelerate it by playing with throttle up to full throttle again, apply to log and it would do the same again. It was at this point I found this site and did some research.

I believe the problem is caused by dirt and sawdust clogging the card. The recommendations were, with this kind of behaviour, to 1) replace fuel line 2) fuel filter 3) impulse line 4) clean carb (and / or carb kit). I then bought all of this, watched some videos on how to tear down saw. I then noticed the play in the sprocket. I spoke with my Stihl guy at the shop where I bought the parts and he informed me that there should be a bearing between the crankshaft (the thing the chain sprocket sits on) and the chain sprocket. This was and is currently missing.

I also noticed some discolored plastic / metal on the chain sprocket. Plastic was a golden brown / burnt brown and the chain sprocket metal blued.

Question/s
* What is the best way to get the plastic shielding off, in front of the cylinder head / spark plug, so I can change the impulse line, is it to remove the casing where the pulley is (starting um handle (please update me with an of the correct terminology))?
* Is it even worth doing carb kits these days as opposed to new carbs for like $30.00?

Thank you all any help you can give, and all the previous posts on this board, it has helped me alot.

Sincerely,

Neoborn

 

[Roll Tide]

Yes there is a bearing between the sprocket and the crank. To remove the cover pop all the caps on the handle and remove it first then the shroud. (After removing your carb) then you will access to the impulse line and will also make the fuel line installation easier. As for the carb depending on what the kit is gonna cost you and what kind of shape its in I'd just throw a new one on there. I'd remove the clutch and check your worm gear to make sure it hasn't been damaged due to the heat. Sorry for the crude instructions I've been out of working on saws for a year or so.

 

[rburg]

Good to see you back Roll Tide. Have you still got all of those saws MM sent you. Lol!

 

[Roll Tide]

Good to see you back Roll Tide. Have you still got all of those saws MM sent you. Lol!

Good to be back! My uncle has the 261 but I still have my 562 and 395.

 

[drf255]

I've worked on a bunch of 025/250's of late.

There were multiple carb setups for the saw. Some had Zama, some Walbro. Some had primer,bulbs, some didn't.

You can totally go with the WT215 replacement carb off Amazon. I think it's like $12 delivered and it works great. The problem you may have is in the rubber shroud/Grommet that encases the H/L needles as they mate against the case. They are all different.

I have extra parts and even a grommet if you need.

 

[Roll Tide]

I've worked on a bunch of 025/250's of late.

There were multiple carb setups for the saw. Some had Zama, some Walbro. Some had primer,bulbs, some didn't.

You can totally go with the WT215 replacement carb off Amazon. I think it's like $12 delivered and it works great. The problem you may have is in the rubber shroud/Grommet that encases the H/L needles as they mate against the case. They are all different.

I have extra parts and even a grommet if you need.

Unless he has an easystart version which he does not, it will not have a primer bulb. The grommets are easily fitted to those carbs. Some only have a hole for the low side adjustment, a drill easily fixes that too.

 

[HarleyT]

To replace the impulse line, it goes from a nipple on the bottom of the block, to a nipple mounted on the inside of the orange rear handle assy.. Taking off the pull starter can give you a better view and access.