4-stroke is coming!

[treeguy347]

Stihl just released their new "4-mix" engine in a couple of their trimmers. The interesting thing is that they run on 50:1 mix. They're little 1.9 cube motors that put out 1.3 hp. They meet EPA phase 2 and CARB regs. Wonder how long it'll be before this gets used on our saws.

 

[stihltech]

4mix

No time soon.

 

[treeclimber165]

Yup, there is some real good info in a couple threads on this from a month or two back. Links to websites with complete drawings, pics of actual working models, etc.

 

[treeguy347]

Stihl's "latest news" page:


http://www.stihlusa.com/news_fourmix.html

 

[sedanman]

I prepped one of the 4-mix trimmers tonite. We ran it in for the customer and checked the high side adjustment with a tach, we got 10,280 rpm out of it with a max permissable speed of 10,500. Idles well, accelerates briskly and is surprisingly quiet. We did a little exploratory surgery on it to look under the valve cover (holy small rocker arms, Batman). I'm thinking of trading my FS75 in on one.

 

[John in MA]

Guys, how would you think this compares to the more normal 4-strokes from Ryobi, Honda, and (It think) Robin?

 

[sedanman]

Diapragm carb and no oil sump mean all position running, a tough feat for a conventional 4 stroke.

 

[seesaw]

Sedanman

Honda's 4 stroke engines are all position (360 degree) OHV. Their new 25cc has an overhead cam even! 10,000rpm and idles at 3,100.
Awesome technology IMO.
Seesaw

 

[Mike Acres]

Go to the Dolmar web page and take a look at the 4-stroke chain saw that they have produced. It has been on their web page for over a year that I know of.

 

[geofore]

trade ins

I know I've had this FS90 too long when the guy says, "Let me get out the micro filtch to look up that part number for you." He doesn't take trade ins even though I said I would like to trade up to a new FS 110. Come to think of it the guy at the parts shop where I got the carb parts for my old Poulan 4000 had to get out the micro stuff too. The poulan is running fine after $110 worth of new parts, just waiting for better weather -4*Saturday and -3* out there now to use it. They get this new 4cycle perfected I'll have an excuse to buy more toys

 

[bwalker]

For the guys that have actually seen a four mix. How does the thing work schenatics wise. Is it simular to shindaiwas dual read vlave design?

 

[timberwolf]

ouch, that is way less than 1 hp / cubic inch

TW

 

[glens]

<b>hp/ci</b>

It's 84% of the value of hp/ci for the two-stroke units when comparing the 85 and 110 trimmers, which have comparable weights and power according to the pages at the web site (with the nod going slightly to the 4-stroker for power/overall_weight).

Inasmuch as it's possible to directly compare the 1.9ci 4-stroke to the 1.6ci 2-stroke engines, 84% of the power/displacement ratio is a lot better than the 50% that half the number of power strokes could imply.&nbsp; There must be quite a marked increase in efficiency.

Anybody reckon there'll ever be subminiature turbochargers for these bad boys?

<b>Dolmar site</b>

That web site is particularly useless in my opinion.&nbsp; Is there a direct link to anything which even closely resembles information regarding the 4-stroke-powered chainsaw Mike referred to?&nbsp; Mike, I see that the DNS knows about wolverine.acresinternet.com again, but that it's evidently not up yet.&nbsp; Any idea when it might occur?

Glen

 

[bwalker]

Throw even a slight amount of money at a fs-85 trimmer for uprgrading and it would stomp this new fourstroke. Huskys new two stroke trimmers post emmisions # that are very impressive. The use a cat and a unique transfer system. Much cheaper and easier to produce IMO.

 

[JimL]

The shindawa trimmer is a piece of ????. reed valves are not on the 4mix. The shindawa has had 2 recall and hasn't hit the market yet.

 

[bwalker]

The shindawa trimmer is a piece of ????. reed valves are not on the 4mix. The shindawa has had 2 recall and hasn't hit the market yet.

Dont be so sure the 4 mix is any better. Its unproven as well.

 

[Grateful11]

That Dolmar site is a about the worst site I've seen in some time. Nice looking saws, what you can see of them. I thought a local dealer was going to take them on sometime back but decided not to.
Grateful
Dolmar

 

[JimL]

Originally posted by bwalker
Dont be so sure the 4 mix is any better. Its unproven as well.

4 mix has been given to some of the bigger landscaping companies, they have had them for a year plus now. Biggest thing to go wrong was a valve adjustment which takes 5 minutes to do.

 

[bwalker]

Shindaiwa did the same with there hybrid. Doesnt meam squat till its in the publics hands.

 

[JimL]

I played with one today, every little piece to it.


Its a solid machine.