Possible new bad gas. What should I do?

[Hermio]

If that's true, it makes my blood boil. So the refineries know this crap causes damage and still sell it to joe public?

It does not damage modern auto engines, as they have materials suitable for it. I have personally never had a fuel-related problem in any of my vehicles, and I typically keep them for 250000 miles or more. They would run longer but the upholstery wears out, and I prefer not to get poked in the butt with springs!

 

[Hermio]

@sean donato, I am not saying your not correct. However I have never had a gravity fed float bowl carb on a small engine vapor lock on me. This includes running high volatility fuel in dirt bikes where the carb is very close to the exhaust and behind the motor.
When I was a kid I do remember my grandpa's Suburban vapor locking. This would have been in the early 1980's. That had a mechanical fuel pump on the block close to the exhaust headers IIRC.

My first chain saw was a Remington. It would vapor lock any time I tried to use it in warm weather. The fuel tank was part of the same casting as the engine block; there was no air gap between the engine and the fuel tank. It just got too hot in the summer; the gas actually boiled in the tank. (I could even hear it boiling when the saw stalled due to vapor lock.)

 

[Seachaser]

Will Red Armor oil help clean up the cylinder on my saws?
What mix ratio would be recommended?

I guess now I just need to know if these cylinders are damaged and if there is anything I need to do to them.

I like Red Armor 40:1. It looks dark like off road diesel. Easy to see if you have the correct mix when you pour.

 

[Khntr85]

Did you take pics or look at the pitons from exhaust side??

 

[bwalker]

They all burn just fine and they do remove carbon on the wet side. Just because no one notices it doesn't mean it isn't happening.

Not from lack of looking.

 

[lone wolf]

Did you take pics or look at the pitons from exhaust side??

He posted some already, I don't see a problem. Go back and tell me. I'm thinking he is good to go, I am pretty sure it was vapor locking that day.

 

[Khntr85]

Ok seen pics…exhaust side looks great however the intake looks like it need looked at…which mean you would have to take all the air filter assembly and such off..


Take this with a grain of salt but I have seen pistons look great on one side and be ruined on the other….

 

[Khntr85]

And once you get good gas you will like red armor, I stopped the stihl ultra and won’t ever go back personally…

 

[ace4059]

Here was the pic of the MS 400 cylinder looking through the exhaust port This was after running RA 50:1 for about 5 minutes. Notice how it cleaned the cylinder wall up. The scratch looks deep on the picture but it’s not bad with the eye.

 

[Khntr85]

Here was the pic of the MS 400 cylinder looking through the exhaust port. ILT his was after running RA 50:1 for about 5 minutes. Notice how it cleaned the cylinder wall up. The scratch looks deep on the picture but it’s not bad with the eye.
View attachment 1160682

Do any of these saws have much run time on them???

 

[lone wolf]

Here was the pic of the MS 400 cylinder looking through the exhaust port This was after running RA 50:1 for about 5 minutes. Notice how it cleaned the cylinder wall up. The scratch looks deep on the picture but it’s not bad with the eye.
View attachment 1160682

We can't make an accurate assessment from that blurry pic take a good clear one!

 

[ace4059]

My guess is less than 15 hours on the 261. Maybe 6 hours on the 400 and probably an hr on the 500. They were new saws. See above. Ran with stihl ultra that I bought with all the saws. I used 2 out of the 3 packs and then switched to RA right before this. I used probably 1 gallon of RA mix at 50:1. Then mixed the new gas of 3 gallons of RA mix at 40:1 which that wouldn’t run so I ran a gallon combined of tru fuel through all 3 in total. The first set of pics where they are black with carbon is after the tru fuel. Not sure what they looked like before.
If I fill up the tanks of all three saws just one time, it takes over 1/2 gallon.

 

[sean donato]

Here was the pic of the MS 400 cylinder looking through the exhaust port This was after running RA 50:1 for about 5 minutes. Notice how it cleaned the cylinder wall up. The scratch looks deep on the picture but it’s not bad with the eye.
View attachment 1160682

looks fine to me. If ut is any sort of issue the gad didn't cause it, and it's still under warranty anyway.

 

[ace4059]

We can't make an accurate assessment from that blurry pic take a good clear one!

This is the only other one I have right now.

 

[lone wolf]

This is the only other one I have right now. View attachment 1160686

Well can you get. clear one later?

 

[bwalker]

Here was the pic of the MS 400 cylinder looking through the exhaust port This was after running RA 50:1 for about 5 minutes. Notice how it cleaned the cylinder wall up. The scratch looks deep on the picture but it’s not bad with the eye.
View attachment 1160682

Safe to say no oil cleans up scratches.
Stop being a spazz and just run it. If you are really worried pull the cylinder and inspect.

I would also inspect your filter and make sure it's sealing properly snd the carb throat isn't dirty.

 

[Khntr85]

So with good gas, do the saws run fine right now????

Ok I read back sounds like they do run, all you can do now is either continue to just run them or break them down all the way…
You would know the more seeing the Intake side…

 

[stihltech]

So they all run OK now.

 

[ace4059]

So they all run OK now.

Yes. They all run just fine now.
Once the gas was replaced with the tru fuel, all three saws started running again.

The consensus where we are at now is the saws were vapor locking with the gas and it was probably a winter blend of gas and nothing is wrong with the gas.
As far as what caused the damage to the intake side of the cylinder, I’m not sure but will but continue to run the new saws as they are.

 

[lone wolf]

Yes. They all run just fine now.
Once the gas was replaced with the tru fuel, all three saws started running again.

The consensus where we are at now is the saws were vapor locking with the gas and it was probably a winter blend of gas and nothing is wrong with the gas.
As far as what caused the damage to the intake side of the cylinder, I’m not sure but will but continue to run the new saws as they are.

Damage to the intake side could certainly be from debris entering past the filter. Like bwalker already stated, check the filter.