ArboristSite.com Sponsors
www.harvesterbars.com


87 octane in ms270?

TnShooter

TnShooter

ArboristSite Member
Joined
Oct 21, 2017
Messages
51
Location
Sourh Eastern USA
Hey guys
I always use 100% gasoline in my equipment and 93 octane.
The only station in my town that had 100% 93 octane fuel no longer sales it.
The only thing I can find in 100% octane is 87. What are the chances I have a problem running 87 100% gasoline.
I use the Stihl UltraHP Synthetic oil.
I guess I should go ahead and say I already bought the 87 fuel and mixed it.
I never knew Stihl required 89 until now. As I always used 93.

My saw is Stock. There are no modifications of any kind done to it.

Thanks for your advice.
 
Ryan'smilling

Ryan'smilling

Addicted to ArboristSite
Joined
Mar 1, 2013
Messages
3,161
Location
Western WI
87 will be fine. Much more important is whether the gas has ethanol, and how long it'll take you to use it up. If it's got ethanol, you've got a month before it's questionable, less if it's stored somewhere damp. Without ethanol, you might get two months give or take.
 
TnShooter

TnShooter

ArboristSite Member
Joined
Oct 21, 2017
Messages
51
Location
Sourh Eastern USA
87 will be fine. Much more important is whether the gas has ethanol, and how long it'll take you to use it up. If it's got ethanol, you've got a month before it's questionable, less if it's stored somewhere damp. Without ethanol, you might get two months give or take.

No, it has NO Ethanol.
It is 100 gasoline. It will probably take less than 2 months if I use it my blower as well.
 
JimmyT

JimmyT

Dolmar PS-5105 S+
Joined
May 6, 2009
Messages
625
Location
Shake Rag Tennessee
Howdy Tennessee Shooter, My red saws turning 14,500 rpms really like that 93 Octane ethanol free with Maxima K2 full synthetic oil at 32 to 1. They run better, more responsive and absolutely no scoring in 11 years.
Best regards from the Volunteer State
 
TnShooter

TnShooter

ArboristSite Member
Joined
Oct 21, 2017
Messages
51
Location
Sourh Eastern USA
100% gasoline, it is like saying,
"100% pure chicken salad."

No doubt there’s some feathers in there somewhere.

Yes, it is a broad term. And incorrectly used often. Just as I did.
Here in foothills of Tennessee, Gasoline that contains NO Ethanol is what we call 100% gas.

I ran down to the dealer and picked up some Stihl MotoMix to mix it with.
I will run 91 Ethanol in it before I pay that price again. Then pour the rest out, run the saw dry, before I put it away.
$35 a gallon. I guess that is better than buying a new saw?

I‘ll drive to the next county over if that’s what it takes to get 91 Ethanol Free Fuel.
 
Mad Professor

Mad Professor

Addicted to ArboristSite
Joined
Jul 2, 2007
Messages
9,391
Location
North East USA
No doubt there’s some feathers in there somewhere.

Yes, it a broad term. And incorrectly used often. Just as I did.
Here in foothills of Tennessee, Ethanol is what we call 100% gas.

I ran down to the dealer and picked up some Stihl MotoMix to mix it with.
I will run 91 Ethanol in it before I pay that price again. Then pour the rest out, run the saw dry, before I put it away.
$35 a gallon. I guess that is better than buying a new saw?

I‘ll drive to the next county over if that’s what it takes to get 91 Ethanol Free Fuel.

Check here

pure gas
 
Ted Jenkins

Ted Jenkins

Firewood by TJ
Joined
Apr 18, 2016
Messages
2,772
Location
Twin Peaks
In almost all cases 87 Octane is the proper rating for saws. Weather temperature and altitude are the factors. Using high Octane will produce less than perfect results. Thanks
 
CausticUC

CausticUC

Need to fix that pull!
Joined
Mar 12, 2019
Messages
441
Location
CA
Aaaaannnndddd let's throw in the caveat: not all country or states calculate the displayed octane levels the same.

There are two numbers that make up pump fuel unless it is marked race or aviation: RON and MON. Race and aviation are RON only numbers.

Typically pump fuel has a combination of ROM and MON, MON is the anti-knock octane rating and RON is research octane rating. Fuel is blended to obtain the pump number at various rates depending on regulations and jurisdiction.

"Most states do not mandate certain standard gasoline grade octane ratings. In the United States and Canada, octane ratings are in AKI, commonly shown as "(R+M)/2". All states require gas pumps to be labeled with the correct octane level and nearly all states do regular testing to make sure gas stations are in compliance."

Take that "correct octane level" statement with a grain of salt.

TN shows: 87 89 91 93 widely available
If the station has 93, you can guess it is being used for the RON in your mixture, otherwise it is likely 91 mixed with 87. Petroleum companies do not ship 89, it is two tank blended at the pump.
 
CausticUC

CausticUC

Need to fix that pull!
Joined
Mar 12, 2019
Messages
441
Location
CA
Oh, and that 87 in your manual likely does not refer to USA and Canada pump 87, it refers to European and Japan which is closer to our 91... well its inbetween 89 and 91.


Japan: Since 1986, "regular" is >=89 RON, and "high octane" is >=96 RON, lead free. Those values are defined in standard JIS K 2202. Sometimes "high octane" is sold under different names, such as "F-1".
 
Mad Professor

Mad Professor

Addicted to ArboristSite
Joined
Jul 2, 2007
Messages
9,391
Location
North East USA
In almost all cases 87 Octane is the proper rating for saws. Weather temperature and altitude are the factors. Using high Octane will produce less than perfect results. Thanks
Knock knock, anybody home? Yep, Det. Det who? Detonation!

Madsens:

1 detonation.png 1 detonation 2.png


According to Stihl:

"

Guidelines for using E10 gasoline in STIHL power equipment:​


If the proper precautions are taken, gasoline containing a 10% quantity of ethanol can safely be used in your STIHL products.


  • Use a minimum of 89 octane gasoline and always use fresh fuel. Only buy enough gasoline that you can easily use up within a two-month period or use a specially formulated fuel mixture like STIHL MotoMix® Premixed Fuel.
 
stihl86

stihl86

ArboristSite Guru
Joined
Jul 27, 2008
Messages
833
Location
Northeast
Hey guys
I always use 100% gasoline in my equipment and 93 octane.
The only station in my town that had 100% 93 octane fuel no longer sales it.
The only thing I can find in 100% octane is 87. What are the chances I have a problem running 87 100% gasoline.
I use the Stihl UltraHP Synthetic oil.
I guess I should go ahead and say I already bought the 87 fuel and mixed it.
I never knew Stihl required 89 until now. As I always used 93.

My saw is Stock. There are no modifications of any kind done to it.

Thanks for your advice.
Use 89 @ 50-1 like they say. Who's "they"? The people who make the saw.
Ethanol will do no harm if saw is used every day(Or often)
Storage is the problem. Which will attract moisture and reduce octane. Around 3 - 4 wks as a rule, but not exact. Maybe 93 will last longer, but why take a chance?
But its a good scapegoat. So don't do 3 other things to aide a problem that doesn't exist in the first place. When all else fails, read the instruction manual.
You can have a problem, a big problem, with 87, given the right circumstances.
Like a dull chain. And a high ambient temp. And a possible already
lean condition. And lending it to a neighbor.
 
JimmyT

JimmyT

Dolmar PS-5105 S+
Joined
May 6, 2009
Messages
625
Location
Shake Rag Tennessee
Stole this from the web: The octane shouldn't affect the temp the engine runs at. The octane rating is only about the detonation properties. If the octane rating is too low for your engine you get pre-detonation (pinging), and damage the engine. This is mostly to do with the compression ratio of the engine. Higher performance engines usually have a higher compression ratio, and so need the higher octane. Nothing to do with the combustion temperature. So if you are running a Dolmar with a Mahle cylinder and piston and its hitting 200 psi then the engine needs the higher 93 octane.
 
Mad Professor

Mad Professor

Addicted to ArboristSite
Joined
Jul 2, 2007
Messages
9,391
Location
North East USA
Stole this from the web: The octane shouldn't affect the temp the engine runs at. The octane rating is only about the detonation properties. If the octane rating is too low for your engine you get pre-detonation (pinging), and damage the engine. This is mostly to do with the compression ratio of the engine. Higher performance engines usually have a higher compression ratio, and so need the higher octane. Nothing to do with the combustion temperature. So if you are running a Dolmar with a Mahle cylinder and piston and its hitting 200 psi then you need the higher 93 octane.

Not according to Madsen's; "The heat caused by detonation made the piston so hot, the rings stuck and seized the piston seized in the cylinder."

Madsen's fuel/mix
 
JimmyT

JimmyT

Dolmar PS-5105 S+
Joined
May 6, 2009
Messages
625
Location
Shake Rag Tennessee
Friction also generates heat due to improper lubrication. Cheap oil and the wrong ratio has caused more P&C scoring than high octane fuel.Go with a good full synthetic oil. That 50 to1 ratio is nothing but EPA garbage. They don't care if you burn your saw up. EPA needs to come to Memphis and take a lot of these worn out smoking cars off the road. One smoking car will put out more pollution in one day than a 1000 saws will in a year.
 
Top