Fuel mix ratio and carb tuning

[huskihl]

Hi RI Chevy
No problem, am learning as I go allong, I test away on my own,
no mentor here to point me in the right direction, that Echo 501
is a great saw, and is the only one that seems difficult to get four
stroking.
But am getting a thermal temprature gun, and when I get the hang of
it, I will try tuning with it and double check with the Tach, am sure a
cool running engine will be much more bennefit to me than listening
for fourstroking which may tell a different tale on every engine, the
temperature however will paint another picture.

Regards, john

Do you already know the optimal temperature that a given portion of the cylinder should read? It's nearly impossible to do any real world testing with an IR gun. You can measure one spot and it'll be 50° different an inch away. Besides, more heat doesnt have to be a bad thing. It takes heat to make power

 

[Greenerpastures]

Until you open the H screw to compensate.....

Yes, opening the H will ensure enough fuel gets in to keep
the engine running cool enough, and we all need to ensure this.
But in doing so there will still be more oil in the system, which is
fine as long as it does not interfear with the plug and spark screen
too much, and over time it will clog the rings.

My own feeling is, ensure you have enough oil in your mix,
ensure you up the H screw to keep your engine cool.
Tuning in my eyes will cool down a saw,
where adding oil will lubricate it.

As long as we know how one effects the other, then we can set up as
we see fit.

 

[Greenerpastures]

Do you already know the optimal temperature that a given portion of the cylinder should read? It's nearly impossible to do any real world testing with an IR gun. You can measure one spot and it'll be 50° different an inch away. Besides, more heat doesnt have to be a bad thing. It takes heat to make power

Yes, heat is generated in the process, and when our saws are tuned well
they tend to run cooler, so measureing this effect can help understand
the results of adding more oil to the mix , or leaning, or riching
does.
Its just a too to help me understand.

 

[Sty57]

I'm confused.............

 

[huskihl]

I'm confused.............

You're in Sconsin. You're Cornfused

 

[huskihl]

Threadkiller^

 

[Wolverine]

If its fat it will never blow. Lol

Wish you’d have told me that before I started dating my first girlfriend.

 

[RI Chevy]

Lol. WTF. Too funny!

 

[huskihl]

Wish you’d have told me that before I started dating my first girlfriend.

I've found the opposite to be true. YMMV

 

[RI Chevy]

LMAO

 

[mdavlee]

I've run 16:1 and have n3ver noticed more heat than 40:1. I haven't run 50:1 in maybe 8 years. Seen too many insides dry and/or blown bearings.

 

[Al Smith]

Back in the day we used outboard motor oil at 16 to 1 .It smoked a little bit but we never cooked an engine .I still contend it's not the oil/gas ratio it's the fuel to air ratio that cooks engines .--the never ending war of the oil .
Oil or not even with a stock saw it's not uncommon to as the day heats up to need a slight turn on the high speed jet .Only takes a second of two .

 

[Greenerpastures]

Back in the day we used outboard motor oil at 16 to 1 .It smoked a little bit but we never cooked an engine .I still contend it's not the oil/gas ratio it's the fuel to air ratio that cooks engines .--the never ending war of the oil .
Oil or not even with a stock saw it's not uncommon to as the day heats up to need a slight turn on the high speed jet .Only takes a second of two .

Well said, I agree that its the fuel to air ratio that does the most damage.
A little more oil is better than not enough, but with modern saws we need
to be carefull, as they don't all take kindly to more oil in the mix.
Two of my saws do not care, the 7900 cared more, and the 362 if I keep her
will be tested on different mixes too, and will get the heaviest she will carry.
I have aspen to run through her at the end of every session to ensure the carb
does not suffer if she sits a while, give me a new 041AV and I won't have that
problem, someting to be said for the older stuff, ours ran on outboard oil and engine oil and anything we had clean about the place and it still runs 40
years later.

 

[sawmikaze]

That is my motto. If its fat, even too fat, it will never blow. Lol

 

[RI Chevy]

True Dat. AND, they come back for more. LOL

 

[retro]

Generally speaking, as 2-stroke engine displacement is decreased AND operating RPMs are increased, the oil/fuel ratio must be increased. Significantly!

Sufficient lubrication for every 2-stroke engine is a direct result of oil migration time AND oil retention time in bearings and other moving parts/friction surfaces that must be lubricated AND cooled by a limited supply. Oil has to get inside/coat every moving surface, stay there long enough to lube, clean & cool and be replaced with new oil at a high rate of supply in small high RPM motors.



Oil does not add heat to a running motor either, it cools it in two ways. Sufficient oil reduces friction which keeps heat low. Oil absorbs heat and carries heat away from everything it comes into contact with so mo' is better.

 

[Greenerpastures]

Yes indeed, oil lubricates, reduces friction and carries conducts heat,
but if you put too much in the mix, then you lean your mix, which
makes heat and puts your oil under even more pressure,
and if you up the viscosity, then the oil will not get into the places it
needs to in time, which will lead to heat build up.
Oil is good, but as the oil is in the mix, then it is a balancin act.

 

[huskihl]

Where's the "kicking the dead horse" emoji.

 

[huskihl]

 

[Greenerpastures]

Is there a reward for kicking said dead horese.