everything except the impulse line is OE. dealer couldn’t get it in a timely manner so that’s the only aftermarket part. It looks fine and fit tightly so I have no reason to believe that’s the problem.
Old stihl 025 running issues. Not sure what to do now !
- Thread starter slowcar281
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everything except the impulse line is OE. dealer couldn’t get it in a timely manner so that’s the only aftermarket part. It looks fine and fit tightly so I have no reason to believe that’s the problem.
SteveSr
Addicted to ArboristSite
When you get this the best way to test is through the spark plug hole with an adapter. This tests the WHOLE system including impulse. Be sure to put an o-ring on the spark plug adapter if it doesn't come with one.
Seal the intake up with a couple layers of bike inner tube between the carb and the gasket. This would probably also work on the muffler side but be sure to put it up against the cylinder behind the cooling plate.
Also check that there is a metal transition plate and paper gasket between the carb and the boot. Make sure that the plate is not bent by putting it on a flat surface like a piece of glass or mirror.
SteveSr
Addicted to ArboristSite
Well, impulse leak can get you two ways... Lets air into the crankcase at the same time that it is starving the fuel pump.
Spent months fixing an 025 from the ground up. Had many of the same issues you had and didn’t but the tools for the vacuum test until I had $150 into the saw. Hardest part other than my own stupidity was finding the exact replacement parts. I found parts for the 250 that said they fit the 025 and didn’t; I noticed someone mentioned the crank seal part number earlier. I remember the frustration when I got the ones for the 250 and had an immediate air leak when I went to pressure test. Also used too much gasket maker on the second attempt and it caused a small leak. Last but not least, the fuel vent on the 025 is the worst. Save yourself the headache and cut the $15 Echo “YOUCAN” replacement vent from HD to size. I wasn’t able to get the OEM Stihl vent to stop leaking fuel and the saw functioned much better with the ECHO vent on. Last but not least, if you haven’t found them yet there’s some solid YouTube videos. Donyboy73 and the1chainsawguy along with a host of others were a great help for me doing the complete rebuild. Good luck!
That kit I bought doesn’t come with a spark plug adaptor unfortunately. Looks like you test through the impulse line with that kit.
Edit: I found an adaptor that screws in the cylinder with a nipple on it that I can hook directly into the mity vac. Seller is away, so it will probably be another week before I get the tools I need. I hate waiting!
fixinsince69
ArboristSite Lurker
I use a mightyvac that does pressure and vacuumYeah one way or another I’ll have to either invest in the correct tools to pressure test it or take it somewhere. For what a dealer will probably charge, I might be able to buy the tools myself.
I don’t have much faith in dealers around here. Years ago before I was familiar with stihl clamshells I called a BUNCH of dealers asking what they would charge to put seals in a 039….. they all refused, wouldn’t touch it, too old….. too much money…..not worth it and told me to just buy a new sawI still have that saw today and it runs great after replacing the seals myself.
I’ll do some research on a vac tester. If someone knows which tester is best and exactly what adaptors I need, I would greatly appreciate it.
Mity vac and adaptors came in today. I pressure tested the saw and it wouldn’t pump up at all. Pulled the flywheel and clutch to spray the seals. The clutch side was fine. The flywheel seal and engine pan area bubbled like crazy.
pulled the piston and cylinder and I believe I used too much rtv.
I’ll get another set of seals, and go a lot lighter on the rtv this time.
I also went ahead and ordered one of those echo style tank vents.
big thanks to everyone that commented and helped!
pulled the piston and cylinder and I believe I used too much rtv.
I’ll get another set of seals, and go a lot lighter on the rtv this time.
I also went ahead and ordered one of those echo style tank vents.
big thanks to everyone that commented and helped!
SteveSr
Addicted to ArboristSite
DO NOT use regular RTV as it is not rated for the higher engine temperatures. Use Dirko HT or the newer Stihl equivalent.
Also, DO NOT use Motoseal as it is not rated for gap filling. The gaps will occur near the seals due to having to hold the bearings tightly in place.
The mating surfaces also have to be PRISTINE clean with all traces of the old sealant removed. A little carb cleaner followed by brake cleaner will help.
See https://www.arboristsite.com/threads/dealing-with-dirko.328794/ for installation tips.
I’ve got a tube of dirko to use. I’ll make sure to clean the surfaces really well.
Looking at the manual it like like you apply a thin coat to the engine pan, and a very thin coat to the outer diameter of the seal.
Looking at the manual it like like you apply a thin coat to the engine pan, and a very thin coat to the outer diameter of the seal.
SteveSr
Addicted to ArboristSite
1. put the cylinder with crank, seals, and bearings in a work stand or wood vise.
2. flip the crank, seals and bearings to the side exposing the seal recess.
3. Put a small bead of Dirko in the seal recess.
4. Flip the crank. seals, and bearings back into position.
5. Run a thin bead of Dirko all the way around the cylinder base and over the seals.
6. Install the cylinder pan noting the oil pump boss.
7. Install engine in main housing and correctly torque pan screws.
Dirko sets pretty quick but I usually leave it to overnight cure and then pressure and vac test.
