Fuel System Maintence Kit for Echo Trimmer

[bertsmobile1]

Have a good look at the carb set up.Nothing to stop fuel under pressure from being pushed out of the main jet and then strait into the cylinder.
Some of the older ones had check valves which were activated by pressure drops in the venturi
However most of them have been deleted over the years.

Very few would get enough pressure to open the metering needle , remember it should have a pop of pressure of around 15 psi and the tank should start to vent around 10 psi
However there are few too many shoulds in that statement and even if the needle is off the seat for a second or two, a lot of fuel can pass through the main jet.

Some of the older 2 strokes had drain plugs in the crank to drain off water, oil & fuel that accumulates in there.

 

[7394]

I have looked at it. & I can see how it could fill the combustion chamber..

But I don't see how it could fill the crankcase ?

 

[bertsmobile1]

Piston rings only seal when they are moving ( or are under pressure )
The inlet port never sees the top of the piston.
It is opened by the under side of the piston skirt, not the piston crown.

 

[7394]

Point taken, no I didn't have the carb or muffler off to see the piston travel.. 2 strokes I don't do anything deep on them, as yet anyhow.

At any rate the trimmer seems to be running fine again.. Plus I still have 1 more year of warranty..

Thanks for all Bert..

 

[bertsmobile1]

Piston goes up creating a partial vacuum in the crankcase till the intake port is uncovered by the BOTTOM of the piston.
Some have cut aways to get a tighter control over this.
Piston comes down blocks the intake off & compresses the crankcase gasses till the TOP of the piston opens the transfer ports to allow the fresh charge to enter the cylinder.
This is why you test the crank case in both compression cause it can blow the fuel air out past the seals
And vacuum cause it can suck fresh air in past the seals so the engine runs very lean

 

[7394]

Certainly appreciate the schooling on 2 strokes... Not my forte, but I like learning new stuff.

 

[7394]

Gave the trimmer a good workout today, runs fine again..

After it cooled I wanted to check the spark arrestor screen & exhaust port. So I took it apart.

Screen was clean, exhaust port only had very minimal soft carbon in it. Soft probably from the Seafoam. Cleaned carefully & thoroughly.

I did spray out the muffler with Brakleen thoroughly, just for good measure (has the Cat in it). After I rinsed it out w/water & blew it dry w/air comp.

Reassembled & fired it up..