Chain Saw Gas

Having a senior moment. I have an old, old saw that says on the fuel cap 16:1, but saws today run much leaner don't they? I was thinking as much as 50:1.

All my Stihls and Husqvarna?s run 50:1 mix.

If that's what it says, then it's correct. I have a Graham/Paige rototiller 1950 two cycle engine that runs 16:1 Straight run mineral oil mixed with gas.

I have 4 saws from 44 years old to almost new, and I run everything 3 oz of oil to the gallon of ethanol free gas, that's about 42 to 1. I think the modern oil is so much better than what was available 40 years ago that it's fine. We bought a new Stihl blower a couple of years ago and I use their oil in that at 50 to 1, it extends the warranty.

This is just silly.

As another poster pointed out, we have much
better oils available today. Your tiller
says straight 30W mixed 16 to 1 because
that is what was available in 1950. Now we
have semi-synthetic and full synthetic
oils, all light years better than 30W.

I have seen tons of old 30W using saws with
carboned up ports from that dino oil.
Don't see that with synthetic. My opinion
is modern saws are more likely to burn up
from the much higher RPMs they run over the
vintage stuff. 9K rpm vs 13K. That and
poor air filtration.

For myself, I use 32 to 1 synthetic in
everything 2 stroke, from my 2 man Disstons
and Homelite muscle saws to my modern high
winding Husky 357.

If you wonder about my qualifications, I
own around 250 saws and have been through
most of them.

And, to clarify, my only point is simply to
say that old oil mix specs are just that,
old and obsolete. Would you insist that
the 30W oil you use also be 60 years old?

Chris B.

That older stuff will run better on modern oil @ 50:1 like Sthil oil. Dad's old poulan which may of been 32:1 ? runs better on it.

The more two stroke lube oil added , the lower the octane of the resulting fuel /oil mix.
The lower the octane . The more likely that detonation will occur. Detonation burns holes through pistons or cracks pistons .

About 10 days ago, I finally sold all of my old Homelite stuff. Included were my Dad's blue XL-12, a new, never used (but 20 year old), late model XL-2, a good XL-2 and a running but high hour XL-2. All saws had new or good bars and new chains. Also included were 4 new 14" chains and one new 14" bar for the XL-2s as well as various carburetors, air filters, spark plugs, sprockets, etc.

On topic, also included was an unopened six pack of Homelite 16:1 oil. I DID instruct the buyer NOT to use the 16:1 oil in the XL-2s because it would clog the fine screens in the carburetors.

Sold everything for $150.

What do you folks think happened?

Dean

I have used Opti-2 for over 18 years and one mix covers all my 2 cycle engines and one is 30 years old and runs great on it. I don't have a bunch of cans with different mixes.

Hey Chris, I agree with you. I have a collection over 50 of them so not quite as bad as you. Have a Disston KB 7 B. What a beast. Lots of Mc Cullochs. Anyway I mix a bottle of oil with 3 / 4 gallon of hi-test gas. That will run anything I have and the synthetic never smokes or carbons up. I would never ever run anything as lean as 1-50. No way! One 650 pro Mc Culloch saw that was at a flea market for $35.oo had so much dino oil carbon in it the DSP valve was plugged solid. Had to gently use a 1/8 brill bit with my fingers to clear the carbon down into the cylinder. After cleaning everything up the saw ran great. Have you ever seen that pancake muffler under that saw solid full of carbon. Just changed it out with another used one and threw it away. Must have weigh close to a pound.

16;1 IS the ratio we used back in the late 50's for outboard motors. The oils today are so much better that you can use a smaller ratio

Ditto

(quoted from post at 11:05:24 05/16/18) This is just silly.

As another poster pointed out, we have much
better oils available today. Your tiller
says straight 30W mixed 16 to 1 because
that is what was available in 1950. Now we
have semi-synthetic and full synthetic
oils, all light years better than 30W.

I have seen tons of old 30W using saws with
carboned up ports from that dino oil.
Don't see that with synthetic. My opinion
is modern saws are more likely to burn up
from the much higher RPMs they run over the
vintage stuff. 9K rpm vs 13K. That and
poor air filtration.

For myself, I use 32 to 1 synthetic in
everything 2 stroke, from my 2 man Disstons
and Homelite muscle saws to my modern high
winding Husky 357.

If you wonder about my qualifications, I
own around 250 saws and have been through
most of them.

And, to clarify, my only point is simply to
say that old oil mix specs are just that,
old and obsolete. Would you insist that
the 30W oil you use also be 60 years old?

Chris B.

Click to expand...

Chris what is silly about it?

The 16:1 ratio and the straight weight
motor oil for 2 stroke mix are both silly.
Both are obsolete standards yet people
still advocate it. All 16 to 1 does is
create smoke and using 30W (very common for
old saws) creates alot of soot in saws.
This leads to carboned ports and pistons
and can lead to carbon breaking off and
scoring skirts. I have lots of old manuals
and many recommend decarbing the exhaust
ports with a wooden stick. How many poor
running motors can be traced back to
clogged exhausts?

I've never seen an oil-rich mix plug up
carb screens. Varnished fuel, sure.
Ethanol is a little sketchy, seems to cause
alot of trouble with tygon fuel lines, but
rubber holds up better. Main thing here is
to avoid old fuel. Dump it in your old
tractor if suspect.

Clogged cylinder fins are another source of
overheating and scoring. Some Homelites
were notorious for this to this point of
Homelite detuning the saw and calling it
fixed. I'm speaking of the SXL925 and the
540. Wasn't exclusive to Homelite.

Start talking outboards and that's a whole
different can of worms.

To each his own.

Chris B.

It's also a leaner fuel mix for the same
amount of gas. Makes a difference. Factor
in ambient temp changes and your carb
settings in the morning may be way off from
the afternoon. They certainly change from
winter to spring.

These new saws with electronic carbs,
strato intakes, self limiting ignitions are
something else altogether. Old rules don't
apply.

Every 2-cycle motor I have uses a different formula. The mower uses 32:1, the weedeater uses 40:1 and the chainsaw uses 50:1

You are, of course, correct. I have been into many of these motors and there is nothing magical about them, nothing in their construction that could say it needs this ratio or that. The bearings are more or less the same and the seals similar.

Couple reasons you would see different ratios might be for warranty (more 2 stroke oil must be better for the bearings!) or emissions (less oil is less smoke is less carbon emitted).

I stick with 32:1 synthetic for this reason for everything. That and pay attention to the tune of your motor, know what it should and shouldn't sound like.

Chris B.

(quoted from post at 04:12:28 05/17/18) You are, of course, correct. I have been into many of these motors and there is nothing magical about them, nothing in their construction that could say it needs this ratio or that. The bearings are more or less the same and the seals similar.

Couple reasons you would see different ratios might be for warranty (more 2 stroke oil must be better for the bearings!) or emissions (less oil is less smoke is less carbon emitted).

I stick with 32:1 synthetic for this reason for everything. That and pay attention to the tune of your motor, know what it should and shouldn't sound like.

Chris B.

Click to expand...

Depends how many of the bearings are needle design or not .

(quoted from post at 04:12:28 05/17/18) You are, of course, correct. I have been into many of these motors and there is nothing magical about them, nothing in their construction that could say it needs this ratio or that. The bearings are more or less the same and the seals similar.

Couple reasons you would see different ratios might be for warranty (more 2 stroke oil must be better for the bearings!) or emissions (less oil is less smoke is less carbon emitted).

I stick with 32:1 synthetic for this reason for everything. That and pay attention to the tune of your motor, know what it should and shouldn't sound like.

Chris B.

Click to expand...

Depends how many of the bearings are needle design or not .

(quoted from post at 05:03:09 05/17/18)

(quoted from post at 04:12:28 05/17/18) You are, of course, correct. I have been into many of these motors and there is nothing magical about them, nothing in their construction that could say it needs this ratio or that. The bearings are more or less the same and the seals similar.

Couple reasons you would see different ratios might be for warranty (more 2 stroke oil must be better for the bearings!) or emissions (less oil is less smoke is less carbon emitted).

I stick with 32:1 synthetic for this reason for everything. That and pay attention to the tune of your motor, know what it should and shouldn't sound like.

Chris B.

Click to expand...

Depends how many of the bearings are needle design or not .

Click to expand...

I would GUESS that all the new saws have needle bearings throughout.But I have taken an old 2 stroker apart that had a plain shell insert on the C/S big end.When it was running at full throttle maybe 6000 RPM.It was 16:1.

(quoted from post at 01:12:28 05/17/18) You are, of course, correct. I have been into many of these motors and there is nothing magical about them, nothing in their construction that could say it needs this ratio or that. The bearings are more or less the same and the seals similar.

Couple reasons you would see different ratios might be for warranty (more 2 stroke oil must be better for the bearings!) or emissions (less oil is less smoke is less carbon emitted).

I stick with 32:1 synthetic for this reason for everything. That and pay attention to the tune of your motor, know what it should and shouldn't sound like.

Chris B.

Click to expand...

Chris, as you appear to be setting yourself up as the authority on two stroke motors and the proper oil-gas ratio, perhaps you could post more advice about getting the right mixture than just "pay attention to the tune". Sound alone can be extremely subjective.

I'm not going to try to claim expert status ion this, but I will give my opinion.

I've owned and used 2 stroke machines for almost 50 years. I've even owned, and used commercially, the Graham-Paige Rototiller someone mentioned way up the page that wanted 16-1 mix ratios. I've had failures at 16-1 and at 50-1. IMO, with most 2 strokes in good condition, ie- good seals, not already worn badly, you can get away with a much leaner mix wit todays oils than you could back in 1965 when it was pretty much straight 30 wt or nuthin'. But you have to use some common sense. The 501- mixes of today are as much recommended to meet emissions standards for small engines as they are for any reason related to performance and longevity. While the old 20-1 30 wt mix was great for keeping the flies out of your face, it causes people to throw a hissy fit when they see it today. Better oils, better designed engines, better bearings, etc. all allow us to use a leaner mix. But there is a trade off point. I believe it varies from machine to machine and varies with conditions, use, temp, machine age, user practices, etc. I regularly run saws designed for 25-1 or 30-1 mixes at about 40-1 using good quality modern oil and FRESH NON-ETHANOL fuel. Clearances in the older stuff differs from todays stuff. I don't use 50-1 ethanol mix in my old Mac 300 or Pioneer P-50. You have to use some common sense. I'd always recommend going a bit richer than leaner. With a brand new machine, follow the makers recommendations. With Uncle Bills 1962 Weed Wizard brush saw...you want to go richer, but you don't need to run it at 20-1 with a good modern oil. Try 30-1 and see how it runs. If it seems hot or doesn't sound right, maybe 25-1 is required. If it runs good you can try 35-1 and see if it still likes it. 50-1 is going to be too lean for a lot of old equipment. Heck, 50-1 is too lean for some not so old equipment! You have to observe and engage the grey cells.

This is why it is so important to use premium gasoline . More tolerance to loosening octane when extra line oil is mixed in.