261C-M Strange Issue

[toppers]

I have a 2020 261cm that has about 10 tanks through it, but all in winter. Today was the first day of warm weather running it (65F). I don't know it it's related but just before this happened, I had an issue cutting some big hard ash and not having enough oil on the chain. It got HOT and I couldn't even touch the clutch drum. So I adjusted the oiler to max and but then it wouldn't stay running afterwards. Not idling well, dying randomly. Could spin it up out of wood, but cut in wood it would die instantly. This lasted for a half hour then I let it sit.

30 minutes later it seemed to clear up and runs as good as ever, I couldn't repeat the problem.

Any ideas? This saw has been flawless and 100% before this.

 

[lone wolf]

I have a 2020 261cm that has about 10 tanks through it, but all in winter. Today was the first day of warm weather running it (65F). I don't know it it's related but just before this happened, I had an issue cutting some big hard ash and not having enough oil on the chain. It got HOT and I couldn't even touch the clutch drum. So I adjusted the oiler to max and but then it wouldn't stay running afterwards. Not idling well, dying randomly. Could spin it up out of wood, but cut in wood it would die instantly. This lasted for a half hour then I let it sit.

30 minutes later it seemed to clear up and runs as good as ever, I couldn't repeat the problem.

Any ideas? This saw has been flawless and 100% before this.

Winter pump gas? Try non Ethanol.

 

[toppers]

It's non ethanol with echo red armor 50:1

 

[lone wolf]

Well pull the muffler and look at the condition of the piston and ring.

 

[buzz sawyer]

does it have the winter/summer window in the air intake?

 

[SteveSr]

I have a 2020 261cm that has about 10 tanks through it, but all in winter. Today was the first day of warm weather running it (65F). I don't know it it's related but just before this happened, I had an issue cutting some big hard ash and not having enough oil on the chain. It got HOT and I couldn't even touch the clutch drum. So I adjusted the oiler to max and but then it wouldn't stay running afterwards. Not idling well, dying randomly. Could spin it up out of wood, but cut in wood it would die instantly. This lasted for a half hour then I let it sit.

30 minutes later it seemed to clear up and runs as good as ever, I couldn't repeat the problem.

Any ideas? This saw has been flawless and 100% before this.

Sounds like classic vapor lock that happens with winter fuel on a warm day. The give-away is that after it sat and cooled off it started working normally.

 

[toppers]

Piston and rings are new looking (red armor rocks). Just checked spark plug gap and it was a weee bit tight to fit 0.020 I had to enlarge it to.

In summer mode during this.

Thanks all!

 

[lone wolf]

Piston and rings are new looking (red armor rocks). Just checked spark plug gap and it was a weee bit tight to fit 0.020 I had to enlarge it to.

In summer mode during this.

Thanks all!

Could still be the fuel.

 

[toppers]

Will look into replacing it then, thanks

 

[lone wolf]

Will look into replacing it then, thanks

Was the saw or can parked in the sun soon before it happened?

 

[toppers]

gas can was not, but saw was definitely in the sun for an hour

 

[lone wolf]

gas can was not, but saw was definitely in the sun for an hour

That will do it.

 

[toppers]

Im not really convinced it was vapor lock, isn't that where the gas shoots out if the cap was opened? It didn't do that when I opened it.

 

[lone wolf]

Im not really convinced it was vapor lock, isn't that where the gas shoots out if the cap was opened? It didn't do that when I opened it.

Hard to say from where I am just see what goes on next time pay attention to temp etc. I have some M Tron saws and they can do odd things from time to time.
Also you said it was the first hot day,the saw got hot and it was also in the Sun so I say fuel possibly, pull the muffler and look at the piston for peace of mind.

 

[PV Hiker]

You can have some vapor lock but not showing evidence in the fuel tank. You mentioned saw was hot and shut it down to adjust oiler. Did you let it idle a bit to get some cool air over the cylinder fins and allow fuel to help cool from inside the cylinder as well. Mtronics are more sensitive to warm up and shut down allowing the sensors to read.

Most likely if it was shut down pretty quickly after a hard long cut it did not bring in new fuel to cool. So what fuel was in the cylinder and carb was vaporized by the motor being heat soaked. Being left in the sun may have kept the saw hot longer.

When you tried to restart there was a issue of trying to draw more fuel in, the computer could have also been confused so it ran like crap. Like you said the 30 minute cool off period had allowed the fuel to flow at normal rate to saturate inside the cylinder and the computer was not wacked out. Even if it did not have a computer you can experience the same situation.

I will try to allow the saw to warm up and cool down and be aware of air temperatures and how I just worked the saw to cool some before shutting down . Keep a watch of fuel tank level and try not to run out of fuel in these hot conditions. If possible keep the saw in the shade when not using.

You may not be in the same situation for a very long time and not encounter what you experienced again, lets hope....

 

[toppers]

You nailed it PV Hiker. I was doing some of the harder cuts I have with this saw, and turned it directly off. Have always been weird about letting it idle because of exhaust building up, etc. but after your post I realize there is a cooling effect I need to use here.

No damage caused here right?

 

[L34]

I have a 441c that I let idle for 30 secs before I switch off.
Also try not to run it out of fuel.

 

[PV Hiker]

@toppers most likely no damage as it is getting some fuel flow but could be a little lean and rich fluctuation during not running very well.