Stihl 025 stalling at idle.. Impulse? Crank seal?

[SteveSr]

I bought some yamabond 4. Any idea if this will work? I'll mic the seals and see if I've got the right ones. Thank you. You probably saved me some costly downtime

Don't know about Yamabond 4. Is it rated for gap filling and does it harden? The Dirko is a high temp (315c) RTV which is rated for both. In any case be sure to pressure and vac test after assembly (with spacers) or after mounting in the main housing. It is better to find any leaks early!

 

[schmauster]

How loose should the oil pump drive gear fit on? Should the bushing be oiled? It doesn't have slop but it spins easily by hand.


I'm not completely understanding how the chain brake works and doesn't stall the motor

 

[Jasonrkba]

I've heard that yamabond stuff is almost a permanent seal, I've never used it though. I used the Moto stuff on my 025 and have had no issues.

Oil pump sounds like it's OK.

 

[schmauster]

Upon reassembly I realized the clutch bands contact the outside of the drum, not the clutch shoes. I get it now.

Does the worm drive gear bushing require lube?

 

[Jasonrkba]

If I remember right I think I put a very thin coat of lithium grease on the threads. I'm not sure if it's recommended or necessary but it's ran great since I rebuilt it.

 

[schmauster]

I'm taking about the inside of the bushing, where it slides on the crankshaft. Not the worm gear on the outside

 

[HarleyT]

It is an oilite beshing, it should spin freely. A smear of grease won't hurt....

 

[Jasonrkba]

I'm taking about the inside of the bushing, where it slides on the crankshaft. Not the worm gear on the outside

Oh, gotcha.

 

[HarleyT]

 

[schmauster]

Thanks guys. Saw runs nicely after the initial smoky startup, tested it in a few cuts today! No weird noises. I need to break out the tach and set the idle speed and mixture screw.

Is it normal for the saw to be oiling while idling? Seems normal by design.

My saw only has the adjustable L mixture screw and idle. Does anyone know which carb would swap over for L and H adjustment?

A larger carb and air filter would be great if anyone knows a candidate.. ive heard Stihls have carburetors that are a bit small for the engine size.

After I sort the carb out a muffler mod will be in order.

 

[Wood Doctor]

Thanks guys. Saw runs nicely after the initial smoky startup, tested it in a few cuts today! No weird noises. I need to break out the tach and set the idle speed and mixture screw. Is it normal for the saw to be oiling while idling? Seems normal by design.

My saw only has the adjustable L mixture screw and idle. Does anyone know which carb would swap over for L and H adjustment?

A larger carb and air filter would be great if anyone knows a candidate.. ive heard Stihls have carburetors that are a bit small for the engine size. After I sort the carb out a muffler mod will be in order.

Mine hardly drips a drop of oil while idling. On fast idle, it will oil much faster as expected.

Be careful on those 025 carbs with two set screws. A few were made with the L screw so far forward that you cannot set them because the shroud blocks it. And, the boot won't work with them either.

 

[Finnrpm]

Check that you have right clutch. Meaning that the round oiler protector plate fits between clutch and wormgear. Mine 023 has (old) original clutch and does not have this plate. You can install the plate but it will lock clutch and wormgear together, so it will be oiling all the time. In the end wormgears wirepin ( the thing that engages the wormgear to the clutch drum notch ) will give up and fails -> no oiling after this..... http://personal.inet.fi/cool/finnrpm/TI_42_2000_30_01.pdf

Walbro WT-215 should fit. http://personal.inet.fi/cool/finnrpm/TI_28_1997_30.pdf

RV

Edited: link added

 

[schmauster]

Good to know. I'll check for the protector plate. Is there a reason i couldn't just use rtv on the worm gear bushing to keep it spinning with the crank? Doesnt seem like it sees much force. I'll order that carb for 23 bucks and be in business.

 

[Finnrpm]

... Is there a reason i couldn't just use rtv on the worm gear bushing to keep it spinning with the crank? Doesnt seem like it sees much force..

No, not really but why oil the chain when it is not moving? Also you might run out of oil before you have to refuel your saw. I believe that is a designed feature on these saws.

RV

 

[backhoelover]

Cleaning and disassembly is happening as I have time. Took purple power to it in the bathtub and showered it off with hot water. (Wife didn't mind :O she's a keeper)
Been super busy lately but it's been raining a lot here in northern California so it's a good time for this



Could be a stiff pump diaphragm maybe. I run 91 w/ethanol mix Cali fuel. The saw has some hours on it. Don't think it's been used daily but I'm sure it sat with fuel/stabilizer for a long time. Carb looks perfect inside from initial inspection. Haven't felt the diaphragm. Been wrenching quite a few years on cars and 4stroke motorcycles. Im fairly new to 2strokes. Been reading a lot on here in my idle time slowly absorbing info.



Changed the impulse line just because it was a pain and in question. The old one looked fine upon close inspection unfortunately. I'm leaning toward the crank seal also at this point. I figure I'll do both if one tests bad. I've ran this saw for a while as it is (stalling at idle) it was recently tuned so I'm guessing that's why it hasn't grenaded yet with the seal(s) leaking. Should I open the motor up to inspect bearings and delete the head gasket for higher compression while I'm in it this far? (If crank seal is leaking) Piston looks great through the ports but i want this saw to be around a long time if I can help it.



That's OK at this point. I just want this thing to be a runner for years to come. Was given to me by family and money is tight for now.



A little back story if anyone cares since I'm guessing I'll be around posting for a bit. Learning from the pros...


New to the forums here. people seem friendly and helpful. Nice site you have here. I've worked for a tree service dragging brush and pulling lines for a few years. Split a bunch of wood for family and friends in the past. Worked clearing trails and cleaning up properties for a few years too. I've stepped it up a little, now I'm doing the odd jobs cutting up trees laying in roads and other little things for friends. Got an old workhorse 8hp Montgomery Ward wood splitter for 500. The guy I got it from had a machinist friend that made it for him. It's a little rough and needed some love. Runs great now and splits anything i can lift into it. Lately I've been given the two saws in my Sig and learning as i go.

Thanks guys!

your wife let you clean you saw in the tube. she gets as wife of the year award

 

[backhoelover]

I bought some yamabond 4. Any idea if this will work? I'll mic the seals and see if I've got the right ones. Thank you. You probably saved me some costly downtime

i took some 025 seals to local bearing and seal dealer and they said they couldnt get them told me that was a special seal made for stihl. was they lying?

 

[pioneerguy600]

Only the Chinese will copy and sell Stihl propriety rights materials, the established businesses that sell here in America would be prosecuted by Stihl if they sold such products. The clutch side bearings for the PRO chassis saws are Stihl propriety and no american business will sell them but the Chinese don`t give a rata azz about copyright.

 

[Wood Doctor]

Only the Chinese will copy and sell Stihl propriety rights materials, the established businesses that sell here in America would be prosecuted by Stihl if they sold such products. The clutch side bearings for the PRO chassis saws are Stihl propriety and no American business will sell them but the Chinese don't give a rata azz about copyright.

Agreed, and your reward is that you will wait an extra two-to-three weeks to receive those parts from China unless a local USA distributor has bought a bunch and has them in stock.