Have I been tuning saws wrong

[Andyshine77]

To be clear, tuning on the rich side is far safer than running lean. Over pressurizing the case Isn't going to happen from running rich, that's not how the firing normally works, except for extreme circumstances and it normally won't harm the bearings.

Over pressurizing the case can in fact happen. Improper blowdown, improper intake timing and inadequate transfer flow, can cause this to occur. All of which is extremely rare, and not going to happen in a normal saw, or at harmful pressures.

And I'm sure none of this helps the average guy just trying get his saw to run well enough lol.[emoji6]

 

[HuskStihl]

I like to set the idle really high, that way my right index finger doesn't get tired squeezing the throttle.

 

[naturelover]

I tune the H so that it isn't four stroking in the cut, and starts to when lifting out of cut.

To me that is a safe tune, and while I did experiment with a cut or two on the Quake saws with a lean tune, I couldn't tell that much difference in that and my settings. There was a small increase, but didn't want to be running on the edge, plus the above stated benefits of a richer tune, and not having to dial it in as much.

As Ron Popiel said, "set it and forget it". To a point, one should adjust for drastic differences in temp or elevations.

However, with the 441C, no need to ever have to worry about that.

As for trimmers, usually set those so that it four strokes at full throttle with no load.

What are thoughts on a blower since it's always under load? I tune those so that it just quits four stroking at full throttle.


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[Chris-PA]

I like to set the idle really high, that way my right index finger doesn't get tired squeezing the throttle.

That reminds me I need to fix the cruise control button on my G621 clone. Darn thing doesn't hold the throttle open.

 

[Chris-PA]

As for trimmers, usually set those so that it four strokes at full throttle with no load.

What are thoughts on a blower since it's always under load? I tune those so that it just quits four stroking at full throttle.

Both trimmers and blowers have quite non-linear loads compared to a free revving chainsaw. The loads increase rapidly, preventing the rpms from increasing the same way a saw does. Since the mixture gets richer as rpms increase, that means the whole relationship to 4-stroking and no-load rev is different. I find with my trimmer that if I try to set it to 4-stroke like a saw it's just pig rich all the time.

 

[MattG]

"Drip down" I'm talking about a carb needle that is no longer seating when it gets warm (pressured ) maybe a vent issue with certain models.

Yo Ex-Englander

I thought this over at lunch break.. The 064 which I noticed this sensitivity to (might add is a very nice saw now)... I bought a very battered, leaky item for 120 english squid I stripped it... test it out... fixed it (leaky cylinder gasket + I give it a carb kit). But I did notice "something weird" with the way it vented... i.e. I *think* (we talked a year ago now) it could build up a slight vacuum. The vent system is very rudimentary... as I slowly discovered... a placcy tube with 1 or 2 grub screws. I cleaned it all up and reassembled etc.. and seemed alright. Certainly has NO RELATED problems and excepting this minor L side carb sensitivity... it is a fantastic saw! I always accept that on a 2-stroke power tool carburetion is a serious COMPROMISE... and you end up just accepting getting the best you can get... well that's how I see it anyway...

PS your mother country is getting it's winter early... no global warming for us in 2016 or so it seems...

Matt

 

[MattG]

was curious where everyone sets there idle

wherever it does not stall... and the chain does not move... what else is needed ?

 

[jmssaws]

Hi WestBoast,

I'll have to think over what you said re. pressurising / venting later on in more detail. No it's my 064 that seems quite sensitive... i.e. I'll the L screw inwards till the lean lope, then back out by like an 1/8. Then sometimes I'll find it harder to hot start, and idle sounds like it bogging on rich... so I just tweek it back in a tad (IDK like a 1/16) and it's all good... smoother idle.. nicer hot start... but there's obv lots of variables here... screwdriver fitting in slot, your ears saying when it;s starting to climb on the lean side etc. etc. I got that 064 at the point where I'm pretty happy wiht it though...

Thanks for your tip though...

On the H side, I just keep on turning it in, then giving it a blast on WOT... and I stop that process once it sounds real clean.. perhaps with just a very slight rough note.

If you happy to help I might even upload a recording of it in the wood... and you can telll me if it's ok... or way too rich...

but I'm certainly happy with it as of now...

A sensitive L is generally not enough pop off pressure,I find that almost every wj on a 1122 could stand a few more lbs especially ported.

 

[jmssaws]

99% of the saws I tune i set the idle with the L,back the idle screw out so it's not touching and then tune it.

A big husky you can't do this way

 

[jmssaws]

I tune a bunch of saws and almost every single one is much to fat,lot of the saws I port I could just tune it and file the chain and send it back to a happy and satisfied customer. A very strong saw can be made a turd with a screwdriver in a second.
Tune is everything

 

[Gypo Logger]

I like to set the idle really high, that way my right index finger doesn't get tired squeezing the throttle.

I just pin the throttle with hockey tape. Lol

 

[HuskStihl]

I tune my trimmer to just barely 4-stroke at WOT with full line on the head. I have no idea if this is correct. It will 4 stroke more as the line wears shorter.

 

[MattG]

A sensitive L is generally not enough pop off pressure,I find that almost every wj on a 1122 could stand a few more lbs especially ported.

Interesting... I might have to PM you sometime on that one jmssaws - if you don't mind? I'm busy with other stuff currently... and that 064 is certainly EASILY good enough for me right now but one day I might go all perfectionist and stuff.....

 

[Amp4027]

Seems like this is a good place to ask:
Around what is the Compression ratio for the tophandle Stihl's? 12:1? 10:1?
What is the correct Exhaust Temperature?
How many gallons does it take until the striations/ribs wear off the piston ring and it fully seats itself?

I like to set the idle really high, that way my right index finger doesn't get tired squeezing the throttle.

That reminds me I need to fix the cruise control button on my G621 clone. Darn thing doesn't hold the throttle open.

I just remove the return spring and use 14ga copper wire to hold the butterfly open.
Every pro and dealer I've met always says: saws only have two workable speeds, Off & WOT. So why not?

I tune the H so that it isn't four stroking in the cut, and starts to when lifting out of cut.

Tried that with a ms193t, doesn't work as well as it did for the 192's I used to use: thing runs like crap in the cut - no power and bogs. I had to tune it just a hair leaner (~1/16 turn) for it to have power to pull that chain in ~10" of log with 93oct eth-free 45:1

 

[Chris-PA]

I just remove the return spring and use 14ga copper wire to hold the butterfly open.
Every pro and dealer I've met always says: saws only have two workable speeds, Off & WOT. So why not?

Just remove the throttle plate - it only restricts air flow anyway!

 

[jmssaws]

Seems like this is a good place to ask:
Around what is the Compression ratio for the tophandle Stihl's? 12:1? 10:1?
What is the correct Exhaust Temperature?
How many gallons does it take until the striations/ribs wear off the piston ring and it fully seats itself?



I just remove the return spring and use 14ga copper wire to hold the butterfly open.
Every pro and dealer I've met always says: saws only have two workable speeds, Off & WOT. So why not?


Tried that with a ms193t, doesn't work as well as it did for the 192's I used to use: thing runs like crap in the cut - no power and bogs. I had to tune it just a hair leaner (~1/16 turn) for it to have power to pull that chain in ~10" of log with 93oct eth-free 45:1

I think treemonkey figured it up one time and it was like 7:1 or something like that

 

[jmssaws]

Interesting... I might have to PM you sometime on that one jmssaws - if you don't mind? I'm busy with other stuff currently... and that 064 is certainly EASILY good enough for me right now but one day I might go all perfectionist and stuff.....

This is the first run and tune after porting,this is how I tune one.

 

[Deleted member 135597]

Do mtronic saws four stroke at all when you lift in the cut?

 

[jmssaws]

Do mtronic saws four stroke at all when you lift in the cut?

Yes

 

[jmssaws]

Do mtronic saws four stroke at all when you lift in the cut?

Beginning of the first cut you can hear it