Stihl 038 avs very high idle

[Fatboy2017]

I have a Mityvac and also this one below, I have saws in this country and abroad and use this one when I'm there, a few years old and to be honest it was well worth the money and has paid for itself many times over! it's aluminium construction. you see some that appear to be the same, but take care, they only do vacuum, just look at the pictures of the gauge and you will see either vacuum only or pressure / vacuum

Car Hand Held Vacuum And Pressure Pump Tester Brake Fluid Bleeder Kit

WWW.EBAY.CO.UK

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22pcs Brake Bleeder Tester Tool Kit Vacuum Pump Motorcycle Bleeding Hand Pump. Suitable for checking pressure and vacuum systems such as: Checking charging pressure...

 

[Ollie_M]

On 14/02/2024 at 18:46, Fatboy2017 said:

I have a Mityvac and also this one below, I have saws in this country and abroad and use this one when I'm there, a few years old and to be honest it was well worth the money and has paid for itself many times over! it's aluminium construction. you see some that appear to be the same, but take care, they only do vacuum, just look at the pictures of the gauge and you will see either vacuum only or pressure / vacuum

Car Hand Held Vacuum And Pressure Pump Tester Brake Fluid Bleeder Kit

WWW.EBAY.CO.UK

---

22pcs Brake Bleeder Tester Tool Kit Vacuum Pump Motorcycle Bleeding Hand Pump. Suitable for checking pressure and vacuum systems such as: Checking charging pressure...

 

Actually bought this and finally got round to pressure testing, blocked it all and couldn’t get saw to hold any pressure whatsoever

 

(yes did confirm tool was holding pressure and my adapters were)

in the end I put my air compressor on it and very quickly came to conclusion clutch side crank seal is shot to bits.

 

oh I can also turn the saw over by hand on just the flywheel with everything blocked off -  can hear the air being pushed out the seals

 

just need to get some new seals ordered and figure out how to get old seals out.

Edited April 6 by Ollie_M

[spudulike]

On 13/02/2024 at 19:51, spudulike said:

I reckon that putting the choke on is pulling through a lot of fuel which has a similar effect to how you adjust the H screw to keep the revs down at flat out running. The very rich mix will stifle the engine at idle thus keeping the revs down. 

You have a real big air leak so a split impulse line, a crank seal that is seriously worn/degraded, loose cylinder, damaged crank case etc. It will be that big that it should be quite visible.

Oh bugger....right again!!

On removing the seal, you can pierce the steel part and lever it out, use the comfortably expensive Stihl kit....yes, I do have one but piercing it and levering out may be the cheapest way to do it.

[Ollie_M]

15 minutes ago, spudulike said:

Oh bugger....right again!!

On removing the seal, you can pierce the steel part and lever it out, use the comfortably expensive Stihl kit....yes, I do have one but piercing it and levering out may be the cheapest way to do it.

What’d be your recommended way to pierce it and lever it out? I was thinking a fairly stout 90 degree pick through a drilled hole but without knowing how much space there is to play with behind metal it’s not something I’m going to try in a hurry

 

oh and fair play on the diagnosis! 

Edited April 7 by Ollie_M

[Muddy42]

16 hours ago, Ollie_M said:

What’d be your recommended way to pierce it and lever it out? I was thinking a fairly stout 90 degree pick through a drilled hole but without knowing how much space there is to play with behind metal it’s not something I’m going to try in a hurry

 

oh and fair play on the diagnosis! 

 

Yes you are on the right track.  I ground an old screwdriver to a point and then bent it at an angle. You can use this as a lever after drilling a few tiny holes in the middle of the seal.  I made some bits of small bits of wood to use as a fulcrum. Watch out you don't scratch / mark the crank or the surrounding casing.  And when putting the new seal in, you need to lubricate it well and make sure you get the lips of the seal over the shoulder. Replacing seals is not easy. If its your first time, Id probably suggest buying two sets of seals because you will mess it up!

[spudulike]

As above. I used an awl and used another screwdriver as a fulcrum but a very similar method. You have to be careful not to pierce too deeply as the ball race is under the seal but it can be done and it works without any major expenditure on special tools.

[Ollie_M]

Clutch side seal out no problem, drilled 2 2mm holes and started to screw in, pliers under the head of the screw 2 hits on the handle end of pliers for each screw and it popped out.

Happy days

although don’t think the rubber part is supposed to be separate 🤣

 

flywheel side I’m not sure what to do really, no space to get a screw in really so not very sure what to do?

edit: well after some digging I found a screw small enough, and it popped straight out 👍

 

 

Edited April 13 by Ollie_M

[Ollie_M]

talking to myself here but clutch side crank seals backordered everywhere 🙄 got them on order from ls engineers hopefully doesnt take too long

[spudulike]

That seal is FUBAR, L&S are normally pretty good and will phone if the order is going to be delayed. 

[Ollie_M]

5 hours ago, spudulike said:

That seal is FUBAR, L&S are normally pretty good and will phone if the order is going to be delayed. 

I’ve heard there’s Stihl tools to help with alignment when putting the new seals in. Are they worth getting? If so what’s the part number?