I've been playing with a Husky 445, and it took a while but it flashed on me how it works. The 445 had a separate air valve and port with a conventional carb, so it's easier to understand. What's going on is the extra air port flushes the exhaust out with fresh air, and that does 2 main things. 1 - it reduces intake contamination so the engine has a air-air/fuel mix in the cylinder instead of an exhaust-air/fuel mix. That helps improve combustion and power. 2 - it helps prevent raw air/fuel mix from being carried out the exhaust port - this is where the reduced pollution happens, as I understand it. I'm still learning this stuff myself, I'm from the days of loop charging outboards, which was essentially trying to produce a more pure intake charge by using excess air/fuel mix to push out the exhaust as a slug. I'm hoping to further the conversation here, and am totally open to other, possibly better explanations of this system, as I really want to understand it's minutia. It would seem to me, purer intake charge=more power, thus, this system may be hotroddable, albeit a bit harder to understand. Thanks for the lesson!

It is for epa. The air charge is designed to get between the exhaust and intake gasses as they are entering and leaving. The theory is that the fresh unfueled air leaks out at the end of the exhaust cycle instead of unburned intake charge.

Good explanation buddy! That 372 xpxt cylinder looks like has a angry intake when the pist9n is init

Prayers for you and the family Mr. Bell...

Thank you for the tec on the saws my friend. Will continue to send prayers for you and the family. God bless yall and a special prayer for momma and son. ❤️🌲🪓👊🏻🙏

Good one. Appreciate the information. Drive safe.

Very good vid Hopper.

Prayers for you all your family Bellhopper!!!!!!!!!

Morning Bellhopper hope you are having a great day today stay cool stay safe be kind 🙂 and I'm thinking of her and wishing her a speedy recovery and keeping her in my prayers as well.

Continued prayers for y’all and T glad rehab is doing well! 👍👍👍👍🇺🇸🇺🇸🇺🇸🇺🇸🙏🙏🙏🙏

Praying for y'all Bellhopper!! Keep you head up and keep doing what your doing!! Take care, love the ones you hold close and spend all the time you can with them!! Life is short and God is good!! Thank you and God Bless!!

Thanks Bell Hopper. Always excellent explanations.

You explain things well. So basically a stratto saw blows down with fresh air rather than a air fuel mix making it a greener saw so to speak.

I know Echo hasn’t went the way of strato yet, but they’ve changed the cylinder to meet epa regs.

Hang in there buddy, we all pullin for you guys! Definitely learned something in this video! It’s all way above my pay grade though! Take care and stay safe!💚🪓❤️

Diesel engines use something like a strato. They have a hose that runs from the exhaust to the air filter. The exhaust has fins. That causes a vacuum and it pre pulls the larger dust particles off and blows them out the exhaust. Your adding clean air to the exhaust and let's the engine run better and cooler. When the exhaust goes out. Everything gets hot and runs bad . I think this is basically the same thing on strato saws. It adds air at the end of the combustion cycle. To help blow it out and suck new fresh air into the air filter. I don't have a strato yet, but I am really looking at getting a 562 or 550 pretty quick

Prayers buddy hope everything gets better back to normal an everybody gets well. Stay safe an have a good week buddy.

I like more the old ones because i have a 372xp of 2001!

The carb on a stro saw is a little testy to adjust. The air pressure and humidity have a lot to do with it.

Bellhopper, may God Reach out Touch and Heal you, your family and everyone in your united in love community:) God thank you for putting on the Full Armor of God on Bellhopper to protect him and his family from all evil, sin and sickness in this world:) Everyone please keep Bellhopper and his family deep in your prayers, for healing and protection:)

The fresh air charge is supposed to push spent exhaust out. Without raw fuel mix escaping. As you say it creates a lean mix above the piston so they are hotter and burn up quicker

Great video! I'm currently reading Small Gas Engine Repair by Paul Dempsey. It has a section that covers stratified engines. It's a great book with good explanations but I find the diagrams to be a bit confusing. So I really appreciate how you tear down the 2 different engines and show us the differences first hand.

Well explained 👍

Huh? Lol. Mercy buddy

Xtorq won't run with a XP piston either. Found that out back when xtorq saw come out. Got one in for a rebuild and just got regular 372 piston for it. Wouldn't run😂😂took min to figure that out lol

I have three of the Poulan type x-torq, they are the 40 something CC saws. I'm not a fan... They are lazy and fussy as heck. My theory is the air ports just dilute the exhaust. I'm getting ready to try to mod them and get the cylinder from the non x-torq similar saws and I also want to experiment blocking the air port and tracking how the air ports flow. It's very interesting how those saws work. Love the video.

Video starts at 6:10 y'all. :)

Air injection into the crank case.

second

First

Buddy you look run down, needs some rest!

Direct air injection hmmm

I’m pretty much like you I don’t get it either

Purpose of strato aircharge is to block fresh fuel-air transfer into cylinder from escaping exhaust port it is an emissions thing that is actually a plus