On 2007-10-16, SteveB wrote:

"Ignoramus1841" wrote in message
...
I recently bought a Echo PB-755 Backpack Blower to blow leaves in my
yard.

I am very puzzled by it. It is a 2 stroke engine. Takes 50:1 oil.

There is no separate tank/port/opening for engine oil.

The manual has not a single word mention of engine oil (like 10w30 or
whatever).

So, all indications are that this engine needs no oil.

I can hardly believe this as all gas engines I have seen so far needed
engine oil.

Is my conclusion that the engine needs no oil, correct?

i

Iggy, I think you could rebuild the Space Shuttle singlehanded, and am
surprised you don't know this one.

In a four stroke, you have valves. The combustion chamber and crankcase
chamber are two separate chambers isolated from each other. The only time
they cross over is bad rings, bad valve guides, hole in the piston,
excessive wear, bad head gasket, etc. In a two stroke, the gas and oil go
on both sides of the piston, and the oil in the gas lubricates the
crankcase. Instead of valves, a two stroke has ports where the gas/oil mix
moves from one side of the piston to the other. It's exquisitely simple.
Google it up and get some diagrams.

Someone like you that has such a knowledge of how things work will get a
real kick when you see simple diagrams of how this actually works.

Steve, yes, thanks, I have learned something very basic today!

i