2 stroke oil has disadvantages.

[John Engineer]

Hi, Many fuel problems with 2 strokes are related to the "varnishes" or residue that is left in your entire fuel system from 2 stroke oils.
JUST USE REGULAR OIL 15w40 or anything your engine uses at about 50 to 1 ratio and NO RESIDUE will be left to block the jets. 2 hp to 200 hp 2 stroke.
Advantages include cooler piston and more power. Always leaving clean internal bearings with oil (NOT VARNISH RESIDUE)
Leaves your tank very clean.
Disadvantages are : Although hard to find there is a small amount more smoke when cold for about 30 seconds.
Possibly a slightly higher emissions as this is the main reason that special agents are added to 2 stroke oil to vaporize and burn cleaner. However the engine suffers from this lack of lubrication from blocked jets (= less oil) over time.
This is real tested and used practice for many years and not just an idea! Cheers John.

[Cheechako]

It's all we ever used until "2 stroke oil" came out.

[a64pilot]

Well, if you were like us, you used non detergent 30W oil for the chain saws and Lawnboy lawn mower as it was a two stroke too.
We had it for the 1953 Jubilee Ford tractor, but used to use a coke bottle full of it per gas can, I think the can was 1 gl, but that was 50 yrs ago.

I believe we used outboard motor oil for the ski boats though, even way back then, I’m not sure that TCW-3 existed, but there was outboard motor oil sold.

[John Engineer]

Both previous replies are right in my book. Yes we did only use normal oil years ago.
I have used detergent diesel oils --- Right down to ATF oil for gearboxes without any bad effects on motorbikes and outboards since about 1978.
Another thing about many 2 strokes is that they are often have "OVER SIZE" main fuel jets to ensure the motor has plenty fuel + cooling/ lubricating oil.
The old Star Flight/OMC/Evenrude outboards made a special adjustable needle that could slowly close off the main jet until it was lean and reaching maximum power and best fuel consumption.
Normal oil mix this is fine but many 2 stroke oils cause the engine to temporary heat seize or slow down due to the additives in the 2 stroke oil dissipating (burning all) the lubrication oil required to transfer heat from piston to cylinder wall then to cooling water (or fins for air cooled)

I often use a small hair of copper wire twisted inside of the main jets to restrict the fuel flow a little, This causing the motor to stop 4 stroking at lower RPM and higher HP for less fuel. BUT ONLY WITH NORMAL OIL without 2 stroke additives.
I hope my many hours/years of experience helps those that like efficiency and reliability.
Cheers John.

[Thumbs Up]

It won't hurt to use a little motor oil for mix in a pinch but I am calling BS on this. Lubricants are formulated for certain purposes. Mix and match is not good practice. It is fine for your old Lawnboy mower, not your expensive outboard nor our fragile marine ecosystems. You probably mix and match hardeners for different paint systems too. It is all the same stuff right? WRONG! New 2 stroke outboard motor jets are sized perfectly, The reason that you need to restrict them is that they erode over time. Run your 2 stroke to lean and with the wrong lubricant and you will ruin it. We are not chemists, This stuff is more complex than our little brains can imagine. Use the correct products!

[John Engineer]

Dear Mr "Thumbs UP"
I do not mind if someone says I am talking "BS" or similar comments!
I was informed about the disadvantages of 2 stroke oil from a chemist at an oil refinery where I was involved in other tasks at the time. So his information to me was taken by me as correct. The practice in taking a 150Hp V6 Yamaha (Designed 50:1 until 50 hrs)(Then 100:1) was modified by me to produce around 275Hp that was run very hard for racing at 50:1 normal 20w50.
I have used this method on various engines for over 30 years with positive results.
Jets are made from brass like cars used to have. I am sure there are no extreme pressures or abrasives that could naturally enlarge a jet, however a manufacturer would often make a 2 stroke jet slightly larger to compensate an engine from starvation of fuel or overheating due to the lack of oil to transfer heat out.
As for the delicate eco system?
I do not know if proof or testing results of engines using 2 stroke oil with chemicals compared from the Millions of buses, trucks and cars etc. that use different oils.
I like using SAIL but there is always a time when we all pollute our world.
I would like to put any differences aside and all of us work together on real facts that help reduce pollution. 50:1 oil burning for 2 stroke is required by design. 4 stroke is better for the environment but this post was discussing how to keep the reliability of 2 stroke.

If I have affected someones ego? or I have offended anyone this is purely by accident.
As for paints and catalysts! I do not know why you should be trying to insult my character? Sorry if you don't like my thread. I try to help everyone but we know that is never a reality in life.
Good health and we work together on a better future.

[Thumbs Up]

I don't know why jets get eroded but have seen it and was amazed at the improvement by ordering a new main jet for my Tohatsu. The old jet had a noticeably bigger hole. The wire trick does work but is trial and error so tricky to get right. The only varnishes that I find in carbs are from dried up old gas. I don't think that most modern engine oils will even stay in suspension in gasoline. They are designed for a specific purpose. So is our TCW3 two stroke oil. I wouldn't use anything else. Any unburned residue goes straight into the water. Using the right oil doesn't cost hardly any more. Using any old motor oil in your 2 stroke might work fine but I will stand by what I said: It is just wrong! and mr John Engineer, sorry if I insulted your character. But you are giving (in my opinion) questionable advice. (to throw out our specially formulated marine oil because any engine oil or even ATF is better)

[Reefmagnet]

Tohatsu at some time in the recent past, if not still currently, specified sae 30 oil, or even just "engine oil" for lubrication of their loop charged 2 stroke motors.


Years ago someone someone told me that the main issue with water cooled two strokes is fouling of the plugs due to the cooler running of the engine vs air cooled equivalents. Not sure if this is true, but it makes some sense so maybe two stroke oils are better for engines operating at slow speeds for long periods.

[Uncle Bob]

This thread reminds me of that great song "I heard it on the grapevine "

[GordMay]

Originally Posted by Thumbs Up

... I don't think that most modern engine oils will even stay in suspension in gasoline. They are designed for a specific purpose. So is our TCW3 two stroke oil. I wouldn't use anything else. Any unburned residue goes straight into the water. Using the right oil doesn't cost hardly any more. Using any old motor oil in your 2 stroke might work fine but I will stand by what I said: It is just wrong! and mr John Engineer, sorry if I insulted your character. But you are giving (in my opinion) questionable advice. (to throw out our specially formulated marine oil because any engine oil or even ATF is better)

Indeed.
Two-Stroke oil has a much lower ash content than regular lube oil (TCW-3 is ashless). This is required to minimize deposits that tend to form if ash is present in the oil which is burned in the engine's combustion chamber. Additionally a non-2T-specific oil can turn to gum in a matter of days, if mixed with gasoline, and not immediately consumed.
Because 2-cycle oil burns with the fuel, it must be more refined than 4-cycle oil, and it must contain a number of additives. These include detergents to clean varnishes and carbon deposits from the combustion ports, anti-wear agents to protect moving parts, biodegradability components and antioxidants.
Four-cycle oil also contains additives, but the oil isn't designed to burn, so the additives are different.

[John Engineer]

Dear everyone,
I wrote a 2 hour long letter explaining spark plugs, combustion chambers, 2 stroke cycle and much more but my letter never made it to the posting.
That's 5 minutes writing for the normal keyboard friendly person.
I cannot afford more time to help or advise. Sorry but make your own choices.
Kind regards to you all. John.

[Bill Seal]

How about 2 stroke motorcycle oil? Those engines are flogged pretty harshly.

[Lake-Effect]

Originally Posted by John Engineer

Hi, Many fuel problems with 2 strokes are related to the "varnishes" or residue that is left in your entire fuel system from 2 stroke oils.

Hmmm.

We've had a 1983 Suzuki 5 hp two-cyl 2-stroke outboard for 12 yrs. I mainly feed it with Shell's best gas which is allegedly ethanol-free, mixed 50:1 with Shell Nautilus 2-stroke oil. Sometimes I add fuel stabilizer or a shot of SeaFoam if I suspect the tank won't get used quickly.

The engine runs pretty reliably, season after season. One year, just because I saw it on a maintenance checklist, I took the carb off and apart for inspection before spring launch. The carb interior was extremely clean, with just a very thin film of still liquid two-stroke oil. No glazing, varnishing, or build-up. I've never worried about it since. At the beginning of each season, I might squirt some carb cleaner into the running engine... and that's about it for annual carb maintenance.

I am a confirmed believer in fresh gas for outboards; I try always for ethanol-free gas and any leftover boat gas in the fall goes into the truck, and I start with fresh gas every spring.

To the best of my knowledge we have never experienced a clogged jet or "varnished" fuel system. (Truck seems happy too )

From this experience, then: fresh gas plus good two-stroke oil does not leave a problem residue or clog jets. The difference might be in engine usage; we just use ours to get in and out of harbour, or to get somewhere in a dead calm. No outboard racing either . Maybe 2 tanks a year, unless we need longer engine runs during a cruise.

[a64pilot]

Originally Posted by Lake-Effect

Nice to learn that we could use 10W-30 in a pinch, though.

In an emergency, any oil is better than no oil, even cooking oil.
But I wouldn’t unless it was some kind of emergency.
Modern four stroke oils are not formulated to be burned in a two stroke, it’s not going to kill it immediately, but it’s not being used as it was intended, you may get lucky.

[Lake-Effect]

Originally Posted by a64pilot

In an emergency, any oil is better than no oil, even cooking oil.
But I wouldn’t unless it was some kind of emergency.
Modern four stroke oils are not formulated to be burned in a two stroke, it’s not going to kill it immediately, but it’s not being used as it was intended, you may get lucky.

Understood. That's why I later deleted that sentence.