what happens with 2-stroke in a 4-stroke valved engine?

[Dub11]

Not sure i believe that YouTube vid animation by lawnmowerMecca on YouTube, would think the gas oil mix would have to flow to thru the crankcase then up the transfer slot to intake valve. Would like to know how piston down stroke does not pressurize and blow back out thru intake and carb, are there Reed valves?

Fair enough. https://www.stihl.com/4-mix-engine-lightweight-and-with-good-lugging-power.aspx

 

[FergusonTO35]

More weirdness I don't need. If I'm gonna have a four stroke I want a crankcase oil sump and straight gas, preferably with EFI.

 

[r7000]

interested to see how long this 4-mix concept lasts

 

[Dub11]

interested to see how long this 4-mix concept lasts

Right up until everything is electric.

 

[Keith Gandy]

It's called a Stihl 4 Mix. They've been out for a few years.
@Keith Gandy may be able to shed some light

The intake and exhaust is through the topend with a bypass system to the bottomend for lubrication

 

[Mutley]

anyone successfully run a 2-stroke lean mix through a 4-stroke motor (lawnmower) and for how long, or did you have problems?

I have been running 37.5:1 mix through a Honda mower & a Makita 4 stroke blower for about 6 years. The Honda gets used at home about every 2 weeks & the Makita is a work tool that gets used daily.
I've had zero problems so far.

 

[FergusonTO35]

Is Stihl now moving away from the 4 mix engines? Last time I looked at the huge display of them at Rural King every single one was 2 stroke, including the large brushcutters.