On 3/26/2016 6:31 PM, Wade Garrett wrote:
On 3/26/16 12:54 PM, Frank wrote:
On 3/26/2016 11:10 AM, Stormin Mormon wrote:
On 3/26/2016 9:57 AM, Pavel314 wrote:
I have a few two-stroke lawn equipment tools
that use different gas/oil ratios. What is it
in the design of a two-stroke engine that
requires a certain ratio? Is it the compression
ratio? I googled around but couldn't find a good
explanation on why the weed whip needs 50-1 and
the chain saw needs 40-1.

Paul


When I took a small engine course years ago, I asked
the same question. The teacher said the engines are
not at all fussy. As for me, I run 32:1 in everything.
Figure I'd rather run rich than lean. Lawnboy likes
to use the special non smoking oil or some such thing.
I've not tried a Lawnboy engine for anything, not sure
it's needed there either.

I suspect the difference in ratio is based on the
machining and manufacturing -- hard versus soft
steel for example.

My two cycle Lawnboys were finicky about using oil other than theirs so
that is all I used.

I'd use their stuff and ratio in chain saw and week wacker without
problem.

Echo says the mix oil used in their 2 cycle engines has to meet JASO FD,
ISO-L-EGD specs or the warranty is void. Their (pretty expensive) brand
of oil does-- but so do some generics and other less expensive brands.


Don't recall what I was using but shop told me that it was reason I was
having problems that I brought to them. I did not want to inventory
different mixes so used the same in all. I had two Lawnboys, neither of
which would start one spring so I traded them both in for a 4 cycle Honda.