What's on your bench today?

[openspaceman]

On 15/01/2022 at 21:49, spudulike said:

Thank the Lord, I was about to call a Priest for an exorcism 

Sounds like the saw has given it in and started to work again...Hurrah!

That was easy, on with the next one.

I spoke too soon and a gremlin got back in. I took the saw to work for the first time today and it played up, just would not open up to high idle.

 

It coughed and spluttered just like there was a pea from a referees whistle in the jet chamber.

Edited February 4, 2022 by openspaceman
grammar

[spudulike]

Have you unscrewed No 3 on this diagram and blasted a bit of cleaner through it and down the hole it screws in to? 

Stihl MS 181 Chainsaw (MS181C) Parts Diagram, Carburetor C1Q-S122B

WWW.DIYSPAREPARTS.COM

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View Stihl MS 181 Chainsaw (MS181C) Parts Diagram , Carburetor C1Q-S122B to easily locate and buy the spares...

 

[openspaceman]

25 minutes ago, spudulike said:

Have you unscrewed No 3 on this diagram and blasted a bit of cleaner through it and down the hole it screws in to? 

Stihl MS 181 Chainsaw (MS181C) Parts Diagram, Carburetor C1Q-S122B

WWW.DIYSPAREPARTS.COM

---

View Stihl MS 181 Chainsaw (MS181C) Parts Diagram , Carburetor C1Q-S122B to easily locate and buy the spares...

 

Yes I did that early on.

[bmp01]

Beginning to see why this saw got put to one side.

I think you're gonna have to look at the accelerator circuit if only to confirm its healthy (or do like you said earlier, get a replacement carb).

Lots of talk about the primer bulb earlier IIRC, how's that working now? Have you tried running the saw with the primer bulb circuit disconnected ? (The return fom the carb must be plugged if you want to try this).

Edit: a new primer bulb was fitted, probably not that then...

Edited February 5, 2022 by bmp01

[openspaceman]

2 hours ago, bmp01 said:

Beginning to see why this saw got put to one side.

I think you're gonna have to look at the accelerator circuit if only to confirm its healthy (or do like you said earlier, get a replacement carb).

I think you are right but I have problems working with very small things as I have no stereo vision so cannot judge distance close in, as such I favour waiting to find another carb to try or lashing out on a chinese one. I'm working with the saw's owner tomorrow so shall try and do a video.

2 hours ago, bmp01 said:

Lots of talk about the primer bulb earlier IIRC, how's that working now? Have you tried running the saw with the primer bulb circuit disconnected ? (The return fom the carb must be plugged if you want to try this).

I can do this by putting a hemostat on the hose, I'll try tomorrow.

[bmp01]

8 hours ago, openspaceman said:

I can do this by putting a hemostat on the hose, I'll try tomorrow.

Yep that's the sort of thing.

 

I've got a bit of a thing against purge valves this week. ...

 

Small 26cc top handle (chinese) was running ok'ish, put it down for 10 seconds and struggled to start it. When it did finally stumble into life, barely clearing itself, it was pig rich. This was boringly repeatable.

Found nothing untoward in the carb - bit of a surprise.

The light bulb moment was realising the purge bulb, while basically doing its job - for the first instant of pressure on the bulb flowed in the wrong direction (this was during diagnosis, not hot restarts before someone says..). Turns out the one way valve inside the bulb was perished. Not until there was significant pressure on the purge bulb did its internal valve seal.

So, in this case the metering chamber in the carb (that oh so critical control parameter) was more or less connected directly to the fuel tank..... and seeing fuel tank pressure. Further, as the primer bulb fuel return line dipped below the fuel level in a brimmed tank, when engine was switched off the tank pressure (from heat soak) was back flowing fuel into the metering chamber, flooding the engine. 

 

I guess I had previously considered the purge lines being 'after' the carb - they couldn't really upset the carbs operation. This week I've changed my mind. A few extra pulls on the start cord and the simplicity of a carb without extra gubbins definitely trumps the 'easy start' sales pitch.

 

 

Edited February 5, 2022 by bmp01

[Macpherson]

2 hours ago, bmp01 said:

Yep that's the sort of thing.

 

I've got a bit of a thing against purge valves this week. ...

 

Small 26cc top handle (chinese) was running ok'ish, put it down for 10 seconds and struggled to start it. When it did finally stumble into life, barely clearing itself, it was pig rich. This was boringly repeatable.

Found nothing untoward in the carb - bit of a surprise.

The light bulb moment was realising the purge bulb, while basically doing its job - for the first instant of pressure on the bulb flowed in the wrong direction (this was during diagnosis, not hot restarts before someone says..). Turns out the one way valve inside the bulb was perished. Not until there was significant pressure on the purge bulb did its internal valve seal.

So, in this case the metering chamber in the carb (that oh so critical control parameter) was more or less connected directly to the fuel tank..... and seeing fuel tank pressure. Further, as the primer bulb fuel return line dipped below the fuel level in a brimmed tank, when engine was switched off the tank pressure (from heat soak) was back flowing fuel into the metering chamber, flooding the engine. 

 

I guess I had previously considered the purge lines being 'after' the carb - they couldn't really upset the carbs operation. This week I've changed my mind. A few extra pulls on the start cord and the simplicity of a carb without extra gubbins definitely trumps the 'easy start' sales pitch.

 

 

 

Hi, the non return valve theory is something that I've pondered many times but usually parts aren't to be had so it becomes a sticking point in a repair to a low value machine, but..

Most of my neighbours prefer these cheap chinky garden machines and most have several ' broken ' ones in their sheds which I regularly get the pleasure of just.. ' having a wee look at ' .. 

 

They're usually almost new looking [ once cleaned ]and hardly done any work and to be fair I can usually revive them, but the non return valve on the bubble is the one part that I can never really trust and I've long suspected that it's function on these cheap machines is their Achilles heal,  .. apart from the fuel !!... and everything else😅

 

I wonder about the materials used and their resistance to Ethanol damage as the actual bubble itself is often another early casualty of being dissolved into a sticky mush or becoming brick hard and bursting with the first pump, so two different reactions to the fuel, although time may play a part in that.

 

I know most wouldn't bother trying to repair this very new ' scrap '.. but I'm a stubborn bugger and I refuse to be beaten by a simple fuel metering device and totally agree with your ' extra gubbins ' comment👍

 

 

 

 

 

 

 

[peatff]

9 hours ago, Macpherson said:

 

I know most wouldn't bother trying to repair this very new ' scrap '.. but I'm a stubborn bugger and I refuse to be beaten by a simple fuel metering device and totally agree with your ' extra gubbins ' comment👍

 

 

My little Chinese top handle has been no problem since I ran it on Aspen2. When it was on pump fuel and 25:1 oil it was a pig for upsetting the mix and always needed tweaking when it got warm to get it to tick over and it was never left with old fuel in the tank. I did accidentally put chain oil in the fuel tank once and had to strip and rebuild the carb but that was due to my own inattention 😕 

[Macpherson]

2 hours ago, peatff said:

 

My little Chinese top handle has been no problem since I ran it on Aspen2. When it was on pump fuel and 25:1 oil it was a pig for upsetting the mix and always needed tweaking when it got warm to get it to tick over and it was never left with old fuel in the tank. I did accidentally put chain oil in the fuel tank once and had to strip and rebuild the carb but that was due to my own inattention 😕 

 

I don't doubt that at all,.. so to me the inference is that the as cheap as possible synthetic rubber parts of these machines are even more affected by Ethanol than the equivalent quality oem part of a Husky or Stihl for instance.

My village is full of garden machinery that's lasted no more than a season or two of minimal use, so essentially nearly new.... it just seems crazy that this situation is being accepted as ' normal ' and that petrol engines can no longer be run on petrol, most folk have never heard of Alkylate fuel and likely wouldn't pay the price for it even if the local garage sold it, they just keep buying cheap B&Q type stuff as and when..

 

Like I said being a stubborn bugger. when an engine has compression, a spark, a clean carb and is nearly new it simply frustrates me if I can't get it running, and that often leads back to the non return valve, or removing the welsh washer...

 

..As a matter of interest last year one of my neighbours brought me an original American McCulloch strimmer from the '70's [ surprisingly good quality ] which hadn't been running for a very long time but had a Walbro carb with a removable blanking plate with a seal allowing access to the mixing chamber... I 've no doubt that the denial of easy access to this by manufactures on nearly every carb is deliberate.

When I first started working on engines in my early teens the pilot air / fuel mixing chamber on Amal's was a major headache which took me a number of years to get a reliable sort for  👍

[Max 201]

Hi everyone, just new to arbtalk and thought I'd share what I was working on today.

I bought a ms210 off ebay which needed a new piston and cylinder. Thought it would be a nice little Sunday afternoon project.

Took the saw apart last week no problem and after inspection it was clear that the piston and cylinder were indeed scored so went ahead and put yet another order in with L&S engineers. This weekend I went ahead and tried to install the bits only to find out they sent me the wrong piston!!!🤬🤬🤬

As you can see in the pictures the piston hight from the piston wrist pin is a whole 6mm too tall. The tail on the intake side is so long even when hitting the cylinder roof it doesn't clear the intake port. 

First time L&S has let me down like this.

Anyone else have had problems like this?

Edited February 6, 2022 by Max 201