Lube requirements for these older 2strokes are different than newer ones.
One needs to use the mix no leaner than suggested in the original owners manual.
Thought this was covered already…[/
quote]In the 1920s and early ’30s oil refining was more art than science. Quality seemed to depend on the phase of the moon. Evinrude did extensive testing (Everything on the motor was supposed to last at least 1000 hours.) Whenever a perceived failure in lubrication happened, the tendency was to add more oil to the gas. The recommended mix for the Racing 460 was a quart to the gallon. (Yes – one gallon of oil to four gallons of gas)
Government funded research during WW2 brought vast improvements in manufacturing and chemistry. Having to meet government specifications brought more uniformity to the oil industry. Further testing proved that much of the piston scoring thought to be from a lack of lubrication, was from carbon deposits from excessive oil flaking off combustion chambers and getting caught between the piston and cylinder wall. This resulted in less oil being recommended. Lubrication charts from the mid 1950s reflect these changes. . . . . . 😀
Haven’t given my oil rant here for awhile. Don’t know how
much, if any, good it does but I’m not one for giving up.
The 1950’s were the days of black and white TV,
rotary dial telephones, and oscillating fans for cooling
on a hot summer day. There has been tremendous amount
of engineering to bring us huge flat screen, remote controlled
color televisions, air conditioning most everywhere we go
along with it being in the vehicles we use to get there, and
of coarse the smart phones that we have today. This same
effort has been put into developing and improving 2 cycle oils
so they provide better lubrication at greatly reduced amounts
over the straight weight non-detergent 4 cycle crankcase motor oil
listed on these decade’s old charts that was available at this time.
Especially synthetics. Here are 2 examples.
1 – In the late 60’s and through the 70’s I was a pretty serious dirt biker.
At that time you would need to bore the cylinder and install a new piston
at the end of each season. As I remember you could go out .050 before
you needed to replace the cylinder. We would run them 2 seasons and
sell them while they were still worth something and by new ones. In
1975 I bought a 400 MX and broke it in on 24 to 1 Yamalube. Then I
changed to Amsoil 2 cycle oil. To be honest I didn’t run exactly 100 to 1
as that would have been a little over 6 ¼ oz. for 5 gallons and I had a cup
mark at 7 oz. that I used to mix 5 gallons of fuel at a time. I ran that
bike 3 seasons and there was never indication of piston slap where I
normally would have had to bore and replaced the piston each year. 3
years and it never needed a piston rebuild using less oil.
2 – I was heating with wood at this time and its when bought this chain saw.
It got the same mix as the dirt bike. I still have it and used it twice last year
after storms brought trees down here and at my daughters. Its had a lot of
use over the last 40 years and the recoil starter is worn out so its hard to get
started but once I get it going it runs as good as it ever did.
I can understand the fear of damaging a motor so I doubled the amount
and rounded off to 3 oz. per. gallon (I am presently using Pennzoil Marine
Full Synthetic) and run that in every 2 cycle motor, including my outboards,
going on 40 years.
Its in our own best interest to have the same concern for the planet that we
have for these motors. Putting excessive amount of oil into our air and water
for no good reason can jeopardize our ability to even have a place to run them
not to mention the air and water.
https://www.youtube.com/watch?v=RKTZWCFGwo8
If youre having to bore the cylinder and replace the pistons, then its safe to say, that you’re not using enough oil. Dirt bikes and chainsaws work a lot harder than outboards and run hotter. More heat, effects viscosity. I run my air cooled two strokes at 16:1 and no thinner than 24:1. Again folks
Oil is the cheapest thing you will ever put in an engine. A little more oil, reduces the wear, therefore prolonging the life of your engine. Why do we continuously want to skimp on it??