2 stroke vs 4

thinwater

Super Anarchist
1,062
144
Deale, MD
amsoil has a 2 stroke synthetic they say you can mix at 100:1 regardless of the mix ratio specified by the manufacturer https://www.amsoil.ca/p/saber-profe...K8yl3xUc0Yh98AfBbbmM1-6g-MUoaP1EaArujEALw_wcB
although they recomend it for chain saw applocations, which is how i came to have a bottle. not sure why you couldn't use it in an outboard.
Because water-cooled and air-cooled 2-strokes do not run at the same temperature and never run the same 2-stroke oil. This is ... well known.
 

Max Rockatansky

DILLIGAF?
4,031
1,099
Frye,
I know you think you know everything. But… you don’t.

Therefore cite your sources for your assertion that there are different oils for air-vs-water-cooled.
 

Max Rockatansky

DILLIGAF?
4,031
1,099
amsoil has a 2 stroke synthetic they say you can mix at 100:1 regardless of the mix ratio specified by the manufacturer https://www.amsoil.ca/p/saber-profe...K8yl3xUc0Yh98AfBbbmM1-6g-MUoaP1EaArujEALw_wcB
although they recomend it for chain saw applocations, which is how i came to have a bottle. not sure why you couldn't use it in an outboard.
Looking further, I see this, which suggests a 50:1 mix:

 

thinwater

Super Anarchist
1,062
144
Deale, MD
Frye,
I know you think you know everything. But… you don’t.

Therefore cite your sources for your assertion that there are different oils for air-vs-water-cooled.
Fair enough. discussion of TC vs TCW

There are dual use oils. But that does not make it a good idea. A case in point is that the Amsoil 2-stroke oil comes in air cooled and water cooled flavors.Amsoil makes different air-cooled and water-cooled 2-stroke oils

I think this is the one you want, and I'm betting it's good stuff. I don't know about the 100:1 from firsthand knowledge, but most manufacturers toyed with it at some point. The experts don't agree. Amsoil outboard synthetic

Although I was never directly involved in formulating 2-stroke oils, I did formulate other lubricants and engine coolants in a former life. I listened to the 2-stroke conversations and I have worked with the engnieers formulating automotive and marine 4-stroke oils, and they worked with me on my specialties.
 

billsreef

Anarchist
819
445
Miami
I know of old-time fisherman that have a 100:1 tank for trolling and a 50:1 tank for high speed running.YMMV
Was a factory certified Merc outboard mechanic many years ago. One of the things that I learned at the Merc school was that 2 strokes could run with no oil if the RPMs were kept to 1000 or less. It would get you home if that oil injection pump failed. So, yeah, low rpm does not need as much oil, which is why variable ratio oil pumps where made for the oil injection into the fuel. Of course back then, we also called those vro pumps very risky opportunity.
 

kent_island_sailor

Super Anarchist
27,659
5,511
Kent Island!
Was a factory certified Merc outboard mechanic many years ago. One of the things that I learned at the Merc school was that 2 strokes could run with no oil if the RPMs were kept to 1000 or less. It would get you home if that oil injection pump failed. So, yeah, low rpm does not need as much oil, which is why variable ratio oil pumps where made for the oil injection into the fuel. Of course back then, we also called those vro pumps very risky opportunity.
When I flew a 2-stroke powered airplane I did not trust the oil injection pump as far as I could throw the airplane, I disabled it and ran pre-mix.
 

Panope

Super Anarchist
1,544
704
Port Townsend, WA
When I flew a 2-stroke powered airplane I did not trust the oil injection pump as far as I could throw the airplane, I disabled it and ran pre-mix.
I did the same thing, even though I trusted the injection pump a bit more than you did (I could throw the airplane).

85 pounds (The Plane!).jpg
 

billsreef

Anarchist
819
445
Miami
When I flew a 2-stroke powered airplane I did not trust the oil injection pump as far as I could throw the airplane, I disabled it and ran pre-mix.
Bypassing the injection pump and running premix was the common advice when that pump failed on an outboard. Especially on Johnson/Evenrude motors, which seemed to be more problematic... though in hindsight that might have been more of bias from working for a Merc dealer.
 

cheese stick

New member
20
8
Kalifornia
It’s very reliable and easy to start. my only complaint is the fuel consumption is significantly higher compared to a similar in weigh 4 stroke. But knowing someone is having a poop over my 2 stroke almost makes it worth it.

I guess one day I’ll have to replace it with a shakey single cylinder 4 stroke.

 
Last edited:

Kris Cringle

Super Anarchist
3,264
2,900
Speaking of two strokes and oil injection pumps, we had 70s Vespa, with a side car, for a few years.

My son and I were cruising at about 40 on a local road. He was about 8 at the time. Regular ride when the whine suddenly became a single loud metallic chirp sound and the back wheel froze up tight.

Screeeeech,..... Thanks to the side car it was an easily controlled skid.

WTF? We both looked at each other. I didn't know what to make of it but in a few minutes, I kicked it over and it started right up. Hmmm,...

We slowly cruised at about trotting speed for a while and all seemed fine. So I cracked it open again and we were off at 40 again. Then, chirp - screech, and we're back at Zero.

I think it was the first time I heard my son swear. He wasn't having any more of this so he got out of the sidecar.

I opened up the seat to make sure the oil reservoir was full, (I knew it was). Then I noticed the clear tube had slipped off the nipple.
I put it back on (clamped it later) and it started back up. We didn't dare go over 20 home but it ran fine after that.

Italian engineering.

Vespa .jpg
 

2airishuman

The Loyal Opposition
1,000
466
Minneapolis area
I just love the thing though. It weighs about 12 pounds and I can lift it on and off the dinghy with one hand. The gas tank is part of the motor, so no separate tank. It is air cooled so it is smoky but it’s not dumping oil in the water. Basically it has the same motor my gas weedwhacker has so you prime it by pushing the bulb 10 times and it starts right up with a couple pulls, and uses little fuel.
For the same money you could have had a really nice pair of spoons:
1663451305590.png

And for less money you could have had:

1663451162248.png


1663451178606.png
 

2airishuman

The Loyal Opposition
1,000
466
Minneapolis area
amsoil has a 2 stroke synthetic they say you can mix at 100:1 regardless of the mix ratio specified by the manufacturer https://www.amsoil.ca/p/saber-profe...K8yl3xUc0Yh98AfBbbmM1-6g-MUoaP1EaArujEALw_wcB
although they recomend it for chain saw applocations, which is how i came to have a bottle. not sure why you couldn't use it in an outboard.

I know of old-time fisherman that have a 100:1 tank for trolling and a 50:1 tank for high speed running.YMMV

My ~1980s 6hp Evinrude has a decal that says 100:1. I've always used 50:1 out of caution though.

There was an era in the late 1980s and 1990s when 100:1 was a thing and was even recommended by some 2-stroke engine manufacturers. It resulted in a lot of premature engine failures and was largely walked back by the manufacturers and the oil distributors. The main problem when this was walked back, was then thought to be that it provided insufficient lubrication at wide open throttle when the lubrication needs were greatest and the fuel flow to horsepower produced ratio was lowest.

When I flew a 2-stroke powered airplane I did not trust the oil injection pump as far as I could throw the airplane, I disabled it and ran pre-mix.

Bypassing the injection pump and running premix was the common advice when that pump failed on an outboard. Especially on Johnson/Evenrude motors, which seemed to be more problematic... though in hindsight that might have been more of bias from working for a Merc dealer.

Bypassing the injection pump and running premix was and is common advice even when the pump is operating to factory specifications, and is in fact recommended by the most recent service bulletins for several of the motors from this era. In addition to the risk of failure, the field experience over the years was that the oil injection pumps didn't provide enough oil, and like the 100:1 experiment, led to reduced engine life.
 

2airishuman

The Loyal Opposition
1,000
466
Minneapolis area
Fair enough. discussion of TC vs TCW

There are dual use oils. But that does not make it a good idea. A case in point is that the Amsoil 2-stroke oil comes in air cooled and water cooled flavors.Amsoil makes different air-cooled and water-cooled 2-stroke oils

I think this is the one you want, and I'm betting it's good stuff. I don't know about the 100:1 from firsthand knowledge, but most manufacturers toyed with it at some point. The experts don't agree. Amsoil outboard synthetic

Amsoil builds their profits on product line differentiation and selling the idea that they have exactly the right oil for every situation, and that the wrong oil will shorten engine life. The lubricants industry is full of hype.

I don't doubt that there are 2-stroke oils formulated with water cooled vs. air cooled engines in mind. I am skeptical that there is a huge impact on engine life and service needs with the most common use cases. I use TCW-3 oil for my outboard and for the few pieces of OPE I have left that aren't electric, because I am more concerned about stale gas than I am about the right kind of oil.
 

Santanasailor

Charter Member. Scow Mafia
1,360
709
North Louisiana
In the old, OLD Days, we used 30W non-detergent and mixed it one Quart to 4 gallons of leaded regular. Never had a problem with oil issues. Smoked a bit they did, but ran fine. About once every other year or so, the heads got pulled due to blown head gaskets (we ran our little 5 1/2's hard) and in the process the mechanics would clean all the carbon off.

So much for pre teens running up and down the bayou in homemade hydros and Jon boats, trying to set the world on fire with 5.5 horse Johnsons, set too high on the transoms. I got one tank of gas per week, and we never had to nurse it unless, we got to borrow a neighbor's 10 Johnson. It really sucked the gas. The 1950's and early 1960's.

Now the world is going to come to an end, if a couple thousand boaters run motors on the back of their small sailboats that burn a bit of oil. (while jet setters and public officials burn thousands and thousands of gallons of JP4 running around the world pleasuring themselves)
 

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