2 Stroke engine oil mix

[Hans]

How important do you think it is to use the exact mix ratio for a two stroke engine. The reason I ask is I have 3 Stihls (50:1), 2 McCulloch's(40:1) and 1 IDS(recommended 32:1, although the owner's manual says 40:1 is ok) . I have started buying only one brand (Stihl) to avoid this problem but the older equipment is still working ok. If I run 50:1 in a product rated for 32:1 am I just shortening its piston life span by 50% or is it going to seize after 2 tanks of gas. I've never known anyone who used a two stroke engine enough to wear out a piston; something like a carb or such usually seems to die first and ends up being more of a pain to fix than just buying another unit.

 

[cp1969]

I don't think it's that important. The old 2 cycles recommended 16:1. My old Poulan chain saw is supposed to get 16:1 but I've fed it a steady diet of 32:1 to 50:1 for at least the last 10 years and it still runs fine. BTW, a chain saw is a much heavier duty application than, say, a string trimmer or a 2 cycle lawn mower. I would think if anything would crap out from a thin gas/oil mix, it would be a chain saw, and I haven't seen it. My Husky recommends 50:1 and I'm not going to keep two separate mixes around.

 

[Bird]

Hans, just a few personal thoughts on the topic:
First, I tend to agree with cp1969 that it probably isn't too important.
The purpose of the oil in the gasoline is lubrication.
If the engine doesn't get enough lubrication, you'll ruin it and the manufacturer knows it so they may sometimes recommend a little more oil than is really necessary.
A little too much oil probably doesn't hurt anything except foul plugs more quickly, build up carbon in the engine and/or on the spark arrestor in the muffler.
Some of the older 2 stroke engine recommendations were based on "outboard motor oil."
Some of the newer 2 stroke oils, designed specifically for air cooled engines instead of outboards, supposedly provide good lubrication in smaller quantities.

So . . ., you only want to buy the one brand. In my opinion (and I'm no chemist) there should be no problem. If in doubt, mix it just a little bit stronger (not much) than the label calls for, and plan to change spark plugs a little more frequently.

 

[DK35vince]

Hans,
Go with a happy medium,mix them all at 40:1 should work out fine..

 

[njrqs]

While running in, my outboard called for 25:1. Now after that, is uses 50:1.

I always err on the high side. Figuring fouled plugs are better than noisy bits inside !!!

 

[Carl_NH]

Hans,

It's about 32-40-1 ratio pending how accurate your are measuring the gas. I filled up my mix can (2 gal) once with a one gallon milk container and marked the level and add 3.5 -4 oz oil per gallon. I run a Husky 51 saw, a Sthil 420 blower, a Komatsu Leaf blower, Stihl 3000 saw, and Ryobi trimmer cultivator on the same mix. I have used the same 2 cycle oil the last 10 yrs - made by Drydene, now Castrol. (my brother in law works for them so I have a good supply) Only failure I have had is a homelite brush trimmer bought in 82 lost power and compression in 99, 17 years I guess is OK..

Carl

 

[neilw]

I only have two 2 cycle engines one uses 32:1 and the other 42:1. Last year I purchased a 100:1 oil mix from Amsoil. The label claimed you could use this oil safely at a rate of 100:1 for all 2 cycle gas engines. Cost about $6.00/quart.

I've been using it at 42:1 in my 32:1 engine ( an old chain saw ) with I guess 10 tanks of gas/oil. I've seen no known ill effects.

For a multi. ratio person like you I saw a new product in the WWW.countryhomeproducts.com site. These are the DR Trimer people.

The new product looks like a gas can with a smaller tank attached. Connecting both the small tank and the gas tank is a tube with an automatic mixing valve. The mixing valve has a dial to set the ratio you want. Just dial and pour. The cost is $37.95.

 

[Youare]

There are several important things about 2 cycle oil mixes.

1. Always use a chainsaw oil in a chainsaw or anything that has a similar engine like a weedwacker. Stick with a manufacturer's brand of oil such as Stihl, Husky, or any other major brand.

2. NEVER use outboard motor oil in a chainsaw. Outboard motor oil is not formulated to operate in air cooled 2 cycle engines. Outboards are water cooled engines and they run much cooler than a chainsaw. The same is true for motorcycle oils.

3. Never use gas that has been mixed for longer than a month. The lubricating porperties of the oil break down in the gas the longer it sits unused. It is less expensive to mix a new batch than it is to fix an engine that didn't get proper lubrication.

I have two different mix ratio chainsaws, 32:1 and 40:1. I feed them both about a 40:1 mix. I buy the little bottles of oil that mix with a gallon of gas and mix a gallon at a time. Some days I use most of the gallon of fuel, but I don't mind mixing a new batch the next day.

I think it cost less than $3.00 for a gallon of mixed fuel I don't mind not using a portion of that, that is far less than the $600.00 I paid for just one saw.

Randy

 

[cp1969]

I, too, have read that you should not use mixed gas if it's over a month old.

But I can't count the number of times that I've done exactly that (with gas MUCH older than one month) and I'm still waiting to have my first 2 cycle engine failure, and I am no spring chicken.

 

[Ken_NC]

I understand the reason not to use gas mix that is old, but what else can you do with it?? I don't want to dump it on the ground. /w3tcompact/icons/hmm.gif

 

[DK35vince]

Ken,
any two cycle gas i have had sitting for long periods of time i just dump into my wheel horse garden tractor to use it up.
Been doing this for 20 years ..

 

[Anonymous Poster]

OK guys I guess my problem is not in the oil mix. My string trimmer died a few days ago just quit. I pulled the carb off figured that was the problem. I soaked it for about 2 hours and stuck it back on. It fired right on up but when I shut it down to gas it up it won't start again. Would a carb rebuild kit help? Or is it destined for the junk pile? I have had it many years and bought it used. Now its really getting some heavy use.

 

[DVerbarg]

<font color=blue>Last year I purchased a 100:1 oil mix from Amsoil. The label claimed you could use this oil safely at a rate of 100:1 for all 2 cycle gas engines. Cost about $6.00/quart.

I've been using it at 42:1 in my 32:1 engine ( an old chain saw ) with I guess 10 tanks of gas/oil. I've seen no known ill effects. </font color=blue>

About 16 years ago I used the Amsoil 2 cycle oil. It seemed to provide the needed lubrication but it fouled up the spark arrestor on out Stihl FS85 brush cutter. Ended up just removing the spark arrestor as it would only run for a couple hours after a cleaning before it stopped running and needed another cleaning! /w3tcompact/icons/mad.gif

That was while growing up and living with my parents. When I married and had my own equipment I tried using a third party 2-cycle oil and started having problems with my brush cutter. Took it in for warranty work and the dealer cleaned it up and told me the problem was the oil I was using. Should only use the OEM. Bought the OEM oil and have never had a problem since.

 

[Youare]

I understand the problem of disposal of old fuel. Being that I mix only a gallon of fuel at a time any old mix is usually less than a quart. I have an old 1979 truck which usually gets this leftover along with a fresh top off of gas.

Randy

 

[rdln]

This stuff also plugged up the exhaust on my string trimmer and backpack blower. I would not recommend it.

<A target="_blank" HREF=http://www.opti2-4.com/opti-2.htm>Opti-2</A>

 

[Ken_NC]

That's a good idea. Unfortunately, I don't have an old truck; so I need to find someone close by who does. Would you want to move? /w3tcompact/icons/smile.gif

 

[Youare]

My wife would move there in a heart beat, but I'm pretty fond of New England for the moment.

I was just thinking that the place you get your oil changed might take the old gas/oil mix and add it to their waste stream if you had a small amount.

Our local recycle center has a waste oil drum for those who still change their own engine oil. The waste oil gets burned in a cement kiln, a little gas does not hurt a thing.

Randy

 

[ekrampitzjr]

Beware of claims such as the one you say that Amsoil makes--that its 2-stroke oil can be used at 100:1 regardless of what ratio the engine manufacturer recommends. If Amsoil did say this, some engine manufacturers are probably going nuts right about now. I understand the need to try to stick to one ratio when you have different 2-strokes around that use different ratios, but going with such a low ratio simply because the oil manufacturer says to is playing with fire. New engines are far more expensive than oil.

Back in the late 1970s, a certain well-known synthetic oil (not Amsoil) claimed you could go 12,000 miles between oil changes using its product in motor vehicles. Of course, no car manufacturer then, and few today, were saying that if you used this specific oil, you could extend oil change intervals. None of the carmakers then differentiated between regular and synthetic oils in maintenance specs, and this oil became notorious for causing seals and gaskets to leak badly. The 100:1 claim reminds me of this fiasco, which did much to hurt synthetics here in the US. Beware.

 

[BobinCols]

The Amsoil 100:1 oil has been on the market since the late 70's. Their oil can be mixed at 100:1 for air or water cooled engines. If you don't feel comfortable at that ratio it can be mixed at the manufacturer's ratio. A synthetic 2 stroke oil will burn much cleaner than a petroleum oil. The fellows that used Amsoil and it plugged their exhaust was probably not from using this oil. I would run this product at the 100:1 ratio without hesitation for any premix required ratio and do so. Do what you feel is correct.

 

[Anonymous Poster]

I have used Opti-2 for about 5 years as have a multitude of yard professionals in my area. Everyone raves about how great it is! I guess we all have good and bad experiences with the same products.
Greg H