Are my pistons scored? Need advice

[EasyT]

Hi, new guy here, in the wilds of north Florida. Fairly new to chainsaws.

I've had this Stihl MS 311 for a couple of years. It's a great saw, I use it for felling medium to fairly big trees, firewood and general around-the-house stuff.

Here's the deal: I have reason to believe it was used with straight gas, no engine oil added. It stalled on me the other day for no reason, as I was cutting through a downed tree. Then it wouldn't start. I fiddled with it through the morning, and could not start it. I've had problems starting it before but nothing like this. It's always cranked eventually. It would almost start, but then wind down like it had no power, and cut out.

To make a long story short, I was pretty damned steamed - to say the least - but after I got over that I started looking to buy another saw because I heat my cabin with wood and must have firewood.

Then, this morning it seemed to work fine. I only used it for a few short cuts, but it seemed to be OK.

How can I tell if the pistons are scored? I'm leery of using it for any length of time before I can tell what, or if, there is a serious problem. Once the pistons are scored, there's no going back, right?

Thanks for any help you can provide.

 

[knockbill]

Hi, new guy here, in the wilds of north Florida. Fairly new to chainsaws.

I've had this Stihl MS 311 for a couple of years. It's a great saw, I use it for felling medium to fairly big trees, firewood and general around-the-house stuff.

Here's the deal: I have reason to believe it was used with straight gas, no engine oil added. It stalled on me the other day for no reason, as I was cutting through a downed tree. Then it wouldn't start. I fiddled with it through the morning, and could not start it. I've had problems starting it before but nothing like this. It's always cranked eventually. It would almost start, but then wind down like it had no power, and cut out.

To make a long story short, I was pretty damned steamed - to say the least - but after I got over that I started looking to buy another saw because I heat my cabin with wood and must have firewood.

Then, this morning it seemed to work fine. I only used it for a few short cuts, but it seemed to be OK.

How can I tell if the pistons are scored? I'm leery of using it for any length of time before I can tell what, or if, there is a serious problem. Once the pistons are scored, there's no going back, right?

Thanks for any help you can provide.

Welcome,,, pull the muffler and take a look thru teh ports,, you can see the rings...

 

[irhunter]

Welcome,,, pull the muffler and take a look thru teh ports,, you can see the rings...

^^^^^^+1
After pulling muffler. slowly pull on the starter cord, so you can view the entire piston as it moves up and down. Take some pics of piston, and post them here.

Roy

 

[EasyT]

Will do, thanks guys

 

[Bob Hedgecutter]

How can I tell if the pistons are scored? I'm leery of using it for any length of time before I can tell what, or if, there is a serious problem. Once the pistons are scored, there's no going back, right?

Thanks for any help you can provide.

Oh there is "going back" it just gets expensive and mechanical.
You suspect it was run with straight gas- usually you only suspect that if you realise after something goes wrong and you remember oh damn I forgot to add the oil......
Personally I would advise not running it until you have removed the muffler, provided photos for the piston face through the exhaust port and confirmed the rings to be free and piston unscored.
If it is marked you will have to dig deeper and it is likely to cost you a piston and rings minimum, with the added bonus of having to clean any aluminium transfer from the melted piston to the cylinder walls. If you continue to run it and the mix is oil light, it might just cost you a cylinder as well, or it something lets go (busted ring or bearing) it could score the cylinder wall beyond saving.
If a saw develops an unexplained problem, better to fully investigate that problem than continue to run the saw. Many a saveable saw has been ruined over the years by people trying to tune out air leaks and keeping the saw running, repaired when first noticed- the saws would still be running, trying to tune out a fault usually ends up with a burned out top end.
As for straight gassing- most all of us have done that at least once!

 

[david newbie]

Btw, if that saw is anything like the 290, I found replacing the cylinder or piston to be a PITA

 

[Huntaholic]

Straight gas is nothing compared to DIESEL FUEL! Ask me how I know.

 

[Tomos770]

I would say that saw cant sieze on diesel....? It would be just pita to clean everything....

 

[Huntaholic]

I would say that saw cant sieze on diesel....? It would be just pita to clean everything....

Seize? No. Be completely lacking in compression and piston ruined, along with the cylinder? ABSOLUTLEY.

 

[FreakinCoolUsername]

Seize? No. Be completely lacking in compression and piston ruined, along with the cylinder? ABSOLUTLEY.

How did you even get it running on diesel?

 

[Huntaholic]

How did you even get it running on diesel?

I didn't. the dipshat bucking logs on the yard did. I had built a fire that morning before going in the woods to cut and used diesel to start the fire. I sat the diesel down beside the fire but the chainsaw gas and oil was 20 yards away and together at the back of the truck. After I made a few drags I noticed he was using a different saw. I stopped and asked what was wrong with the other one. He said it ran a few cuts, quit, got it restarted and made 2 more cuts and it quit. AT that point I asked him if he used gas or diesel and of course he denied using diesel. There was no denying it when I took the cap off and poured straight diesel out of the gas tank.

 

[REJ2]

Hi, new guy here, in the wilds of north Florida. Fairly new to chainsaws.

I've had this Stihl MS 311 for a couple of years. It's a great saw, I use it for felling medium to fairly big trees, firewood and general around-the-house stuff.

Here's the deal: I have reason to believe it was used with straight gas, no engine oil added. It stalled on me the other day for no reason, as I was cutting through a downed tree. Then it wouldn't start. I fiddled with it through the morning, and could not start it. I've had problems starting it before but nothing like this. It's always cranked eventually. It would almost start, but then wind down like it had no power, and cut out.

To make a long story short, I was pretty damned steamed - to say the least - but after I got over that I started looking to buy another saw because I heat my cabin with wood and must have firewood.

Then, this morning it seemed to work fine. I only used it for a few short cuts, but it seemed to be OK.

How can I tell if the pistons are scored? I'm leery of using it for any length of time before I can tell what, or if, there is a serious problem. Once the pistons are scored, there's no going back, right?

Thanks for any help you can provide.

You’ve had it and used it for a couple of years and you believe it may have straight gassed? Did you loan it to someone without instruction? Just curious.

 

[FreakinCoolUsername]

I didn't. the dipshat bucking logs on the yard did. I had built a fire that morning before going in the woods to cut and used diesel to start the fire. I sat the diesel down beside the fire but the chainsaw gas and oil was 20 yards away and together at the back of the truck. After I made a few drags I noticed he was using a different saw. I stopped and asked what was wrong with the other one. He said it ran a few cuts, quit, got it restarted and made 2 more cuts and it quit. AT that point I asked him if he used gas or diesel and of course he denied using diesel. There was no denying it when I took the cap off and poured straight diesel out of the gas tank.

That sucks, but how did he confuse gas and diesel. They look completely diffrent. What kinda saw was it?

 

[Huntaholic]

Umm you don't know the dipshat that did it! LOL he tried to blame it on me, since both cans were red LOL. Yeah, I made him pay for a new topend. Husqvarna 576xp. I do all the felling, all he does is buck logs on the yard and hes tore up 10x as many saws as I have! Just in the last year hes destroyed or damaged saws 5 times. Crushed 1 with the knuckleboom, ran over 1 with the wheel loader, destroyed 2 fuel tanks on a 461 and dropped a log on 1 with the knuckleboom. Good help is IMPOSSIBLE to find!

 

[Bob Hedgecutter]

That sucks, but how did he confuse gas and diesel. They look completely diffrent. What kinda saw was it?

Easily confused by modern day kids that learn from a 5" screen.
Had it happen to me, young guy down on his luck was living with us, set him the task of mowing our lawns (4 stroke Briggs) while we were out working to support his sad ass and rather than heed the instructions about where the gas can was, he went a hunting and found a similar looking can to a gas can- but it was yellow, filled the tank, shagged the mower, went and got my other mower- filled it from the same YELLOW can and proceeded to fork it as well.
Cost me two new motors.
That kid does not live with us no more.

 

[a. palmer jr.]

Usually when you straight gas a saw it won't run anymore unless you just use it briefly that way. You can always check the compression and see how much it has. Around 150 is about right, 90 means it needs rebuilt..

 

[REJ2]

Umm you don't know the dipshat that did it! LOL he tried to blame it on me, since both cans were red LOL. Yeah, I made him pay for a new topend. Husqvarna 576xp. I do all the felling, all he does is buck logs on the yard and hes tore up 10x as many saws as I have! Just in the last year hes destroyed or damaged saws 5 times. Crushed 1 with the knuckleboom, ran over 1 with the wheel loader, destroyed 2 fuel tanks on a 461 and dropped a log on 1 with the knuckleboom. Good help is IMPOSSIBLE to find!

Sounds like no help would be more cost effective! Doesn’t make sense to keep him around, period.

 

[FreakinCoolUsername]

Umm you don't know the dipshat that did it! LOL he tried to blame it on me, since both cans were red LOL. Yeah, I made him pay for a new topend. Husqvarna 576xp. I do all the felling, all he does is buck logs on the yard and hes tore up 10x as many saws as I have! Just in the last year hes destroyed or damaged saws 5 times. Crushed 1 with the knuckleboom, ran over 1 with the wheel loader, destroyed 2 fuel tanks on a 461 and dropped a log on 1 with the knuckleboom. Good help is IMPOSSIBLE to find!

Sheesh, he really dosn't like his job does he.

 

[cookies]

Umm you don't know the dipshat that did it! LOL he tried to blame it on me, since both cans were red LOL. Yeah, I made him pay for a new topend. Husqvarna 576xp. I do all the felling, all he does is buck logs on the yard and hes tore up 10x as many saws as I have! Just in the last year hes destroyed or damaged saws 5 times. Crushed 1 with the knuckleboom, ran over 1 with the wheel loader, destroyed 2 fuel tanks on a 461 and dropped a log on 1 with the knuckleboom. Good help is IMPOSSIBLE to find!

Take him to the saw store during lunch one day out of the blue without warning then get him to finance his own, supply the fuel/oil/chains but his attitude will change with that payment he will be making.

 

[FreakinCoolUsername]

Take him to the saw store during lunch one day out of the blue without warning then get him to finance his own, supply the fuel/oil/chains but his attitude will change with that payment he will be making.

I have to agree That is probrobly the best way to solve that problem.