2 Cycle Mix

[8ntruck 7,021]

I dug my old  (15, 18 years) 18" Craftsman chainsaw out today to get it ready for some use on my 20 acres in Ky. in the near future.  To my surprise, it started after four or five pulls of the rope.  The saw is old, but has little use - maybe 10 hours.

 

The gas cap says to use 40:1 fuel mix.  The rest of my (newer) 2 cycle equipment runs 50:1 mix.

 

Think there would be any harm running the modern 50:1 mix in this saw?  Some of the current 2 cycle oils claim to be universal, covering the range from 20:1 to 50:1.

[ebinmaine 67,671]

Most of my 2 stroke engines require 50:1. 

My new Craftsman leaf blower states 40:1. 

I'd rather use a little more oil than be concerned about the mixes. 

My "Mix" gas can has 40:1 or even a little stronger.  

[JoeM 7,874]

I've used 50:1 in all my two cycle engines for a few years now and no issues. Switched when I got some Stihl stuff and did not want to have two different cans. 

 

I use Stihl Synthetic HP 2 cycle oil with non e gas. Stihl doubles their warranty if this oil is used.

Edited November 15, 2021 by JoeM

[Handy Don 12,237]

16 minutes ago, 8ntruck said:

I dug my old  (15, 18 years) 18" Craftsman chainsaw out today to get it ready for some use on my 20 acres in Ky. in the near future.  To my surprise, it started after four or five pulls of the rope.  The saw is old, but has little use - maybe 10 hours.

 

The gas cap says to use 40:1 fuel mix.  The rest of my (newer) 2 cycle equipment runs 50:1 mix.

 

Think there would be any harm running the modern 50:1 mix in this saw?  Some of the current 2 cycle oils claim to be universal, covering the range from 20:1 to 50:1.

Doesn't surprise me that it is ready to go back to work. I'm also running one of these old Craftsman (Roper) saws. I don't second guess--it asks for 40:1 and that's what I give it. It is on an Alaska sawmill attachment with a ripping chain and it works hard. BTW, there is a following for these saws, if you search around on the web.

Newer saw engines have different metallurgy for cylinder sleeves, pistons, and rings, as well as other internal rotating parts, that can handle less lubrication. Your saw will run, but it'll run hotter and wear faster.

[Snoopy11 5,714]

What size is the fuel tank on it?

 

You could always put a little more oil in the tank of the saw, rather than mixing a different blend. 

 

That is what I do for one of my weed eaters... requires 35:1... so I used an online converter... and figured out how much oil it would need to make it 35:1...

 

Don

[8ntruck 7,021]

 Good idea Don.  I'll do a little research and work out how much I'd need to add.

 

@JoeM I currently have the Sthil oil in stock.  Bout a six pack to double the warranty on the Sthil string trimmer I got earlier this year.

[formariz 11,987]

Personally I would stick with the 40:1 if that is what it calls for regardless of claims in newer oil. It is inconvenient to have different cans for different mixtures but I would not chance it. I have an arborist’s Makita that is really a Dolmar and that takes a 23:1.  I also have a very large Makita( another Dolmar) that states if Dolmar oil is used it is 50:1. Any other brand oil used however it should be 40:1. That makes me think that they don’t trust other oils and would rather be safer recommending a 40:1 mixture using other oils. 

[lynnmor 7,309]

My old Homelite chainsaws are 16:1, or 32:1 if you use the Homelite 32:1 oil.  I mix Ace Hardware low ash oil at 32:1 and use it in my Stihl trimmer as well.  The Stihl would plug up the exhaust screen with oil that wasn't low ash.

I have an Echo backpack blower that specifies only FD rated 50:1 oil and minimum 89 octane gas.  They would void the warranty if anything else was used.

I recently sold a 1957 Elgin outboard that specifies just about any oil, 2 cycle or 4 cycle as long as it is mixed 16:1, I warned the buyer to not use leaner mixes due to large plain crankshaft bearings.

 

I'm just pointing out that 2 cycle oil has changed considerably over the years and all you can do is take your best guess.

[Maxwell-8 4,277]

I have a ton of chainsaws, new and old  I use 40:1 on all.   It is very important you use a high quality oil! If you use a cheaper oil, you need to use more of it.

running a bit more oil won't harm it, to little sure will.

 

My ms880, I sold to buy my first horse. 

 

So I did with my Jonsered 2188 (Husqvarna 390)

 

My current MS661

 

Also in my concretesaw which has to be floored for sometimes a full tank of gass, while under high load

 

[SylvanLakeWH 25,604]

I’ve always gone a bit rich… never regretted it and have had no issues…

 

[Snoopy11 5,714]

Here is the thing about 2 stroke engines... (this is some technical knowledge from racing groups that I have followed around... and learned from)...

 

So... backpack blowers don't run 10,000 rpm... whereas, chainsaws hit 10 grand and more. This is where it needs more oil. If you run under 10 grand, you could use less oil. However, where more oil is necessary is when those rpms go over 10,000. 

 

It really all depends on rpms, not really much else involved in oiling of these engines.

 

If it was a backpack blower, I wouldn't care as much. However, I personally have some souped-up backpack blowers and chainsaws, and I run over 40:1... much closer to 35:1-32:1...

 

I do that on purpose. Running too much oil in a stock blower will cause spark plug fouling over time... as it does not create the rpm's to both expel and burn the excess oil. However, if I was to run less oil in my performance 2 cycle engines, it would begin to annihilate the cylinder walls and piston rings, which would be detrimental on my investments. 

 

I say, never a good idea to take a chance on running less oil. Perfectly fine to run more than enough... perhaps even WAY too much oil. But not enough... that will turn it into a grenade. 

 

Don

[Maxwell-8 4,277]

1 hour ago, Snoopy11 said:

So... backpack blowers don't run 10,000 rpm... whereas, chainsaws hit 10 grand and more. This is where it needs more oil. If you run under 10 grand, you could use less oil. However, where more oil is necessary is when those rpms go over 10,000. 

Don't now which Jonsered, but one is the highest revving chainsaw ever produced, close to 16.000rpm !!!!

[Snoopy11 5,714]

8 minutes ago, Maxwell-8 said:

Don't now which Jonsered, but one is the highest revving chainsaw ever produced, close to 16.000rpm !!!!

Probably runs 25:1 oil ratio...

 

I've got one that is 60cc... BRUTICUS!!! 

 

Don

[Snoopy11 5,714]

I've got a backpack blower that is over 80cc...

 

Like a hurricane on your back... 

 

Don

[8ntruck 7,021]

Good discussion.

 

Upshot is, follow the manufacture's reccomendations, or favor a bit more oil in the mix.

 

I'm at that age where this saw will probably be the last one I'll buy.  Treat it nice and keep it going.

[Snoopy11 5,714]

3 minutes ago, 8ntruck said:

favor a bit more oil in the mix

 

 

Don

[8ntruck 7,021]

17 minutes ago, Snoopy11 said:

I've got a backpack blower that is over 80cc...

 

Like a hurricane on your back... 

 

Don

Careful where you point it.  It might knock you over.

 

I keep thinking about modifying the ait intake on my battery powered leaf blower.  Cut the intake grating out and 3D print a flared intake collar to improve air flow into the blower. 

[Snoopy11 5,714]

4 minutes ago, 8ntruck said:

Careful where you point it.  It might knock you over.

 

I keep thinking about modifying the air intake on my battery powered leaf blower.  Cut the intake grating out and 3D print a flared intake collar to improve air flow into the blower. 

Not a bad idea... Looking at the differences in my 48cc blower compared to the 80+... mostly the tubing is bigger, the fan is more aggressive, and the intake grating is exceptionally large...

 

Don

[Snoopy11 5,714]

8 minutes ago, 8ntruck said:

Careful where you point it.  It might knock you over.

HAH! Yes, that and... it is really heavy... so blowing around the pond is a little... eh... tedious... 

 

Don

[8ntruck 7,021]

14 minutes ago, Snoopy11 said:

HAH! Yes, that and... it is really heavy... so blowing around the pond is a little... eh... tedious... 

 

Don

Put a canoe in the pond and use the blower to make a 'jet'powered canoe.

[Maxwell-8 4,277]

40 minutes ago, Snoopy11 said:

Probably runs 25:1 oil ratio...

no, I believe 50:1 but states to use 25:1 if you don't use their oil. So they mean the cheap oil.

[WHX?? 48,833]

20 hours ago, JoeM said:

I've used 50:1 in all my two cycle engines

Went the other way on this and use 40:1 canned fuel in everything. Had a Crapsman blower too that wore out a piston. Was under warranty yet and they fixed it free but I got ripped a new one for not running 40. I may have very well put some 50 saw gas in it.... Since then it's always been 40 in everything including the 4 stroke weed wacker... ...

I use the canned fuel because of the ungodly shelf life and it might be a year or three before I pick up that saw again. If I know I am going to go thru a couple of tanks on a wood pile I'll go back to hi test pump gas mixed, The canned stuff goes for about 17 bucks a gallon. 

[ebinmaine 67,671]

11 minutes ago, WHX?? said:

I use the canned fuel because of the ungodly shelf life and it might be a year or three before I pick up that saw again. If I know I am going to go thru a couple of tanks on a wood pile I'll go back to hi test pump gas mixed, The canned stuff goes for about 17 bucks a gallon

Everything we have is 90 or 91 octane Non E gas. I don't ever let ours sit for more than a few months though and our 2 strokes are almost always run dry before shelving. 

 

Your canned gas is expensive but it's worth it for the assurance. 

[WHX?? 48,833]

39 minutes ago, ebinmaine said:

 

Your canned gas is expensive but it's worth it for the assurance. 

I think so and I don't go thru alot of it and it is SUPPOSED to be hi test and E free and top quality oil or so they claim. One thing fer sure is they do start easier after a sit. 

I used to run dry too but found if the implement of destruction has those tiny rubber fuel lines I find they dry  rot in the tank. Some of my not go to saws & wackers sit for a long time. 

[8ntruck 7,021]

Well, I got the saw out into the woods today.  Filled it up with a 40:1 mix of Opti-2 and alchlolfree premium.

 

Made 6 or 8 cuts in a log, then the saw quit in the cut.  It would start and idle, but bog out when I opened the throttle.  I suspect it has ingested some crud into the carb.

 

Today's job was to clear the fallen logs off of the trail.  After the saw quit, we ended up skidding the logs off of the trail with a come along and levering them about with a shovel.  Would have gone quicker and we would have gotten more done if the saw had not quit.