MS880 seized, again!

[pleasant]

4 hours ago, peatff said:

 

That's the fuel to oil ratio, a weak mixture in usual terms is the carb adjustment air to fuel ratio running high revs with the H screw turned in.

A weak mixture is a weak mixture. If it goes in the tank to begin with with less oil than it should have to give proper protection then its a weak mix irrelevant. Adjusting the carb will reduce the amount of mix or increase it, compared to air ratio, but it wont change the ratio of mix in the machine as the two are pre-mixed already. It wont add more oil if the mix is incorrect to begin with. Ie it wont change the mix ratio.....unless you have a machine like a moped of old whereby you could manually increase or decrease the volume of oil entering the fuel via a seperate reservoir. When you adjust your H and L settings on your carb, all you are doing is altering the air/ fuel mix ratio. Not the oil/petrol mix ratio.

Edited December 19, 2022 by pleasant

[openspaceman]

9 minutes ago, pleasant said:

A weak mixture is a weak mixture.

We are having a misunderstanding.

 

"Weak mixture" is generally understood to mean the petrol to air mix has too little petrol in either 4 stroke or 2 stroke engines and says nothing about the lubrication.

[pleasant]

1 hour ago, openspaceman said:

We are having a misunderstanding.

 

"Weak mixture" is generally understood to mean the petrol to air mix has too little petrol in either 4 stroke or 2 stroke engines and says nothing about the lubrication.

I was trained by stihl many moon ago when it comes to describing failures and the reporting thereof.  A weak mix is the pre mix entering the tank. A lean mix or leaned out mix is a mix that has been weakened by the introduction of too much air via carburettor adjustment and/or air leakage

Edited December 19, 2022 by pleasant

[spudulike]

In short, if anyone believes that using more oil in the fuel will cause the machine to seize....fill your boots, go for a 15:1 mix fuel to oil and try to rev the saw up flat out. It will smoke like feck and rev poorly.

Anyone who has been in the repair game a while has had that homeowner saw come in that isn't revving and smoking like mad. The fuel is drained and comes out the colour of cherryade....."oh yes, I was told 25:1 but I mix in a little bit more" is the owners response.

Try it, fill your boots....a LEAN mix is too much AIR to FUEL mix caused by carb setting or air leak! Fuel = OIL and Petrol.

[pleasant]

Yup, spot on Spud

[peatff]

5 hours ago, pleasant said:

When you adjust your H and L settings on your carb, all you are doing is altering the air/ fuel mix ratio. Not the oil/petrol mix ratio.

 

Which is what I said in my post😉

[pleasant]

Had a guy once who seized a sprocket nose up in one weekends use. Blued the rails as well. It was a new saw we sold him- came in with the bar and demanded a new one. Looked at it and sure enough it had generated a lot of heat- guy was adamant he had put oil in the chain reservoir as he had bought a litre of it from us when he purchased the saw and said there was still oil in the reservoir after he had issues with the bar. Told him we needed the whole saw, bar and chain brought in for us to investigate. First thoughts were oiler not oiling. When it came in all looked like it should do- except when we drained the chain reservoir the oil that came out was bright red. Rang the guy, and said looks to us like you've put 2 stroke oil in the chain oiler. He said that's the oil I got from you' Yes, we said, but this is the oil you mix with the fuel- not for lubricating the chain. 'oh' he said, 'I thought the same oil did both!'

 

 

[spudulike]

18 minutes ago, pleasant said:

Had a guy once who seized a sprocket nose up in one weekends use. Blued the rails as well. It was a new saw we sold him- came in with the bar and demanded a new one. Looked at it and sure enough it had generated a lot of heat- guy was adamant he had put oil in the chain reservoir as he had bought a litre of it from us when he purchased the saw and said there was still oil in the reservoir after he had issues with the bar. Told him we needed the whole saw, bar and chain brought in for us to investigate. First thoughts were oiler not oiling. When it came in all looked like it should do- except when we drained the chain reservoir the oil that came out was bright red. Rang the guy, and said looks to us like you've put 2 stroke oil in the chain oiler. He said that's the oil I got from you' Yes, we said, but this is the oil you mix with the fuel- not for lubricating the chain. 'oh' he said, 'I thought the same oil did both!'

 

 

Yup, seen MS181 oil tanks stained red by that! And the list goes on.

[pleasant]

33 minutes ago, spudulike said:

In short, if anyone believes that using more oil in the fuel will cause the machine to seize....fill your boots, go for a 15:1 mix fuel to oil and try to rev the saw up flat out. It will smoke like feck and rev poorly.

Anyone who has been in the repair game a while has had that homeowner saw come in that isn't revving and smoking like mad. The fuel is drained and comes out the colour of cherryade....."oh yes, I was told 25:1 but I mix in a little bit more" is the owners response.

Try it, fill your boots....a LEAN mix is too much AIR to FUEL mix caused by carb setting or air leak! Fuel = OIL and Petrol.

We use that colour description of how a mix should look to help the weekend warriors.

 

Not cherryade, more salmon pink is correct. It does help them to understand.....plus upselling a measuring bottle! 😆👍

[wyk]

Every time someone brings in a saw to me that is big and burnt, it invariably has a dull chain and poor maintenance. No amount of 25:1 oil is going to save your saw if you habitually stuff it into a stump with a bad chain and worn bar. Eventually the heat will win.

Edited December 26, 2022 by wyk