strato saws

[sand sock]

i am buying another saw pretty quick. . i have only experience with the traditional saws.
i think i understand what strato saws are trying to do, compared to big diesel engines. add a vacumn to the iar filter and dump the clean air in the exhaust. it pulls more air in faster as it exits the exhaust. making it run cleaner and cooler. diesel engines actually pull larger particles of dirt awayfrom the air filter.and gets pushed right out the exhaust. [not what the saw will do. it just adds clean air at the end, to finish the burn.]


i saw a few people say that there was concearns that the bottom end, might not be getting enough lube. but those were dated concearns. any problems down in the bottom lately? my old stihl 361still runs good, just thinking i should get another spare saw. looking at teh 562 but wouldnt mind picking up a 550 later for pruning work. i have only been around the husky 460 and that impressed me. i want to stay in the proline up. thoughts?

 

[Franny K]

Isn't the Husky 560 the small bar mount European model of essentially the 562?

The fuel injected Stihl is not a Strato design, might consider just waiting for more fuel injected choices.

My understanding is the strato saws and other 2 cycle engines using the principle have a fuel/air and an air passage starting at the carb location. The air makes it into the cylinder first hence is what chases the exhaust out.

 

[sand sock]

Isn't the Husky 560 the small bar mount European model of essentially the 562?

The fuel injected Stihl is not a Strato design, might consider just waiting for more fuel injected choices.

My understanding is the strato saws and other 2 cycle engines using the principle have a fuel/air and an air passage starting at the carb location. The air makes it into the cylinder first hence is what chases the exhaust out.

460my bad (edited). Looking at a husky

 

[bwalker]

i am buying another saw pretty quick. . i have only experience with the traditional saws.
i think i understand what strato saws are trying to do, compared to big diesel engines. add a vacumn to the iar filter and dump the clean air in the exhaust. it pulls more air in faster as it exits the exhaust. making it run cleaner and cooler. diesel engines actually pull larger particles of dirt awayfrom the air filter.and gets pushed right out the exhaust. [not what the saw will do. it just adds clean air at the end, to finish the burn.]


i saw a few people say that there was concearns that the bottom end, might not be getting enough lube. but those were dated concearns. any problems down in the bottom lately? my old stihl 361still runs good, just thinking i should get another spare saw. looking at teh 562 but wouldnt mind picking up a 550 later for pruning work. i have only been around the husky 460 and that impressed me. i want to stay in the proline up. thoughts?

Strato saws absolutely have less lubricant passing through them than a traditional two stroke. On top of this they have heavier pistons which tax the lower end more.
Franky K explanation of how a strato works is spot on.

 

[LuDookie]

Not sure if they are meant to run cooler. My only strato saw is my 261, and it’s a torch compared to my other.

 

[snobdds]

Strato saws have nothing to do with decreasing lubrication. They just add air after combustion to aid in complete burn. They actually make the exhaust cooler as well...

 

[Old2stroke]

Lots of misunderstanding of how a stratified charge chainsaw engine works but it really doesn't matter. Bottom line is it's an unnecessary complexity that does nothing to improve the performance and makes correct tuning more difficult. MIGHT reduce emissions a little, I don't think the engine runs any cooler and doesn't seem to use less fuel. The duel throat carbs are more complex, cost more and even though you find a good tune, it never seems to hold for very long.

 

[Maintenance supervisor]

I have 2 MS441 stihls that run very well with a little bit of woods porting. Compared to my 044 and 372 they are stronger and burn less fuel. Thays my experience with them.

 

[Lionsfan]

Who cares whether or not it's a strato-saw? Pick out a saw you like that suits your needs and your budget, mix your gas 40-1 and run it.

 

[bwalker]

Not sure if they are meant to run cooler. My only strato saw is my 261, and it’s a torch compared to my other.

They run hotter for certain.

 

[bwalker]

Lots of misunderstanding of how a stratified charge chainsaw engine works but it really doesn't matter. Bottom line is it's an unnecessary complexity that does nothing to improve the performance and makes correct tuning more difficult. MIGHT reduce emissions a little, I don't think the engine runs any cooler and doesn't seem to use less fuel. The duel throat carbs are more complex, cost more and even though you find a good tune, it never seems to hold for very long.

They run much cleaner and use less fuel.

 

[bwalker]

Strato saws have nothing to do with decreasing lubrication. They just add air after combustion to aid in complete burn. They actually make the exhaust cooler as well...

The lower oil use wasn't a design goal but anytime you put less fuel through a crank case charge two cycle you use less oil.
The air they ass has nothing to do with combustion. It's about scavenging the cylinder with air instead of fresh mix.

 

[esean]

I've only got one (MS 362), but tuning has not been a problem.

 

[ballisticdoughnut]

Only strato saw I own is a 545 mark II. I prefer straight old piston ported saws. Having said that, I can’t say a bad thing about them so far. That 545 is the best sounding/running 50cc saw I have.