Possible new bad gas. What should I do?

[bwalker]

I too encountered old, bad gas from neighbor who borrowed tiller my tiller and it wud not start; I removed gas, removed water, tried again, still no hit/ no start; removed and installed MY gas and it fired/ ran fine first pull. I 100% think you are wrong; at MIN, on multi-cylinder injected, I suspect wud generate 300 codes.

I have put old skanky gas in my truck and it runs just fine.. how many bad gas stories do you hear from modern car engines?
As it pertains to small engines guys blame everything on gas or sprakplugs...I have had budies do this when in reality the engine was just flooded.

 

[Chevboy0167]

These work. Bought 2 sizes myself and tried them with some old fuel sitting around. Stopped and trapped the water. Not a drop got through.

https://mrfunnel.com/Mr._Funnel/Home.html

 

[lone wolf]

Here’s the replies to the questions I see for me over the last two pages.

I put some regular gas that’s in question in a glass mason jar. I didn’t get home from Ft. Worth until 2am. Now I’m heading to Amarillo. I won’t be back home for a few days. I took a photo and I’ll take another one of the gas when I return. But it looks good now.

Yes, I use the pure gas website. It is accurate around where I live.

As far as if there is any damage? That’s really why I posted photos. The shop here in town thinks the lines on the back of the cylinder of the 261 is caused from the pin at the split that holds the rings. You can’t see the vertical lines in that cylinder because I can’t get the correct angle with the camera. The shop said they would be more concerned with what looks to be pitting on the cylinder.

On the 400, you can see the polished marks that look like vertical lines on the back of the cylinder. The tech said that looks like dirt ingress and damaged the cylinder.

Techs said they can’t tell if it has “bad gas” damage. That’s why at this point I am asking for other opinions.

Repost those pictures I don't think they are easy to see, that's why you aren't getting many responses to them.

 

[ace4059]

Repost those pictures I don't think they are easy to see, that's why you aren't getting many responses to them.

Can you not click the link and see the photos?
Also the photos should be displayed on my post where you can slide left or right and look through them.
Are you not able to see the pictures? I hosted them through Imgur.

Edit:
I’ll just upload them here and if need be a mod can delete them if it’s against site policy. I know some sites don’t want them loaded directly to the site because it uses too much bandwidth on there server and they on want the pictures hosted by a third party.

 

[ace4059]

This is the photos of the fuel. These were taken about 5 minutes after pouring it into the jar. I checked an hr later and it looked the same. When I get back to town, I look again. It will probably be Friday evening.

 

[ace4059]

Here is a re post of the pictures of the pistons. I’ll load them directly on here.

This is the ms 261 looking through the exhaust port. As said before, the 261 does have two vertical lines (more like two polished marks than actual gouges) in the cylinder by the intake port. I can get a photo of them because the way you have to hold the phone, and saw it blocks the camera lens but you can see it with your eye when you hold it as a certain angle.
The back of the cylinder looks “rough”.
The piston looks great.
I’ve only used 50:1 stihl ultra until this happened which I switched to red armor 40:1 and it would not run on this gas.

 

[ace4059]

Here is the MS 400 CM
Piston looks great.
Might be some scoring or scratches on the back cylinder. Any advice is appreciated. Sorry some photos are turned sideways

 

[sean donato]

Diaphragm carbs have pressurized fuel in them. At least from when they hit the fuel pump to the metering cavity. float carbs can vapor lock just as quick as anything. Kohler v twins were bad for it. Used to happen in carb auto applications when manual fuel pumps were a thing too. Electric pumps more or less took care of that issue. Even efi can vapor lock, but it's much more unlikely with the pressure in the fuel rail.

 

[sean donato]

This is the photos of the fuel. These were taken about 5 minutes after pouring it into the jar. I checked an hr later and it looked the same. When I get back to town, I look again. It will probably be Friday evening.
View attachment 1160123View attachment 1160124

Fuel looks fine, not that thay means much. I didn't see anything other then the scratches in the back of the 400 cylinder that I'd be concerned about causing poor running in multiple saws. I didn't notice you mention, but have you tried fuel from another source? I'm inclined to agree with the winter fuel on a hot day, as we haven't switched to summer fuel yet around here. The switch should be soon though.

 

[ace4059]

Yes all three saws run just fine on other fuel. The only common denominator that caused all three saws to stop running was the fuel.

Any concern about the back of the cylinder on the 400? What causes that? Or is that just normal wear?

 

[muddy42]

Ethanol isn't blended in at the refinery because we don't want our equipment like tanks and pipelines damaged.
It's blended typically at the loading rack.

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

 

[lone wolf]

Can you not click the link and see the photos?
Also the photos should be displayed on my post where you can slide left or right and look through them.
Are you not able to see the pictures? I hosted them through Imgur.

Edit:
I’ll just upload them here and if need be a mod can delete them if it’s against site policy. I know some sites don’t want them loaded directly to the site because it uses too much bandwidth on there server and they on want the pictures hosted by a third party.

Sure you can, no one will delete them here. I don't see any damage in the clear pics. I can surmise that the fuel was causing your saws to vapor lock, keep the fuel can and saws out of direct sunlight as much as you can.I bet they will run fine in a cooler temp.

 

[sean donato]

Yes all three saws run just fine on other fuel. The only common denominator that caused all three saws to stop running was the fuel.

Any concern about the back of the cylinder on the 400? What causes that? Or is that just normal wear?

Don't know what caused the scratches, does look like there's some carbon built up, but thats nothing more then conjecture on my part. I personally wouldn't worry about it at this point, and tbh without tearing into it there no way to know if there is anything going on.

 

[sean donato]

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

The refineries didn't mandate the ethonal in the fuel, the government did. They don't care how corrosive/hydroscopic it is, they don't care that its not actually saving money, not doing jack for the environment and they even have the reports from the late 80's- early 90's that prove its nothing more then a farce.

 

[bwalker]

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's absolutely true. And refiners don't make ethanol in most cases and don't want to use it. However, the EPA mandates we do.

 

[bwalker]

The refineries didn't mandate the ethonal in the fuel, the government did. They don't care how corrosive/hydroscopic it is, they don't care that its not actually saving money, not doing jack for the environment and they even have the reports from the late 80's- early 90's that prove its nothing more then a farce.

Ethanol is essentially a welfare scheme for farmers and agri business. And the tax payer is left footing the bill and holding the bag when it damages aequipment.

 

[bwalker]

Diaphragm carbs have pressurized fuel in them. At least from when they hit the fuel pump to the metering cavity. float carbs can vapor lock just as quick as anything. Kohler v twins were bad for it. Used to happen in carb auto applications when manual fuel pumps were a thing too. Electric pumps more or less took care of that issue. Even efi can vapor lock, but it's much more unlikely with the pressure in the fuel rail.

@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.

 

[lone wolf]

@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.

Well the fuel must have changed for one right?

 

[thenne1713]

I’ll have to read through the posts and answer any questions you asked me at a later time.

Here are pictures of the 400
Pics of MS 400 CM piston and cylinder wall

In this, your PIC, you can see the MAGIC MARKER LIKE CARBON TRACKS on the ring/ piston, and it was LESS than that locked a Ring in the groove on day 2 of a new saw like GLUE, name brand oil, 40:1 dino.

In another example, CSM tested with new piston/rings for x-hours one at 40:1, one at 50:1, one at 100:1; Results was carbon at 40:1 similar to yours, 50:1 was CLEAN, and 100:1 left some slight scoring. He agreed w/ MFR that 50:1= Best. Your mileage may vary.

 

[thenne1713]

In this, your PIC, you can see the MAGIC MARKER LIKE CARBON TRACKS on the ring/ piston, and it was LESS than that locked a Ring in the groove on day 2 of a new saw like GLUE, name brand oil, 40:1 dino. I have run synthetic 50:1 since. My repair was $12 piston ring, slight scratch in cyl, Dealer wanted $640 as CS out of warranty.

In another example, CSM tested with new piston/rings for x-hours one at 40:1, one at 50:1, one at 100:1; Results was carbon at 40:1 similar to yours, 50:1 was CLEAN, and 100:1 left some slight scoring. He agreed w/ MFR that 50:1= Best. Your mileage may vary.