EDT 7 Tach

[thewoodlands]

Purchased this Tach from the local Stihl dealer, looks like Wednesday night I'll start checking the saws. I was told by one of the owners of the shop to bring it to the maximun rpms (9500) then back it down 250 rpms, he said all the classes he took that is what they recommend.

zap

 

[MasterMech]

It depends on the saw. That's not a bad guideline. Remember not to get too hung up on the numbers themselves. Also get a baseline BEFORE you change anything. That way you know where you're starting from and you can get back to there if need be.

If Stihl says the saw should be turning 9500 then you won't hurt it setting it there. Nice thing is, you can play. Set it to 9500, How do you like it?

Then figure out what the absolute max is (adjust the H until it won't turn any faster) and back it off the 250 or so RPM's. How do you like it?

Then you could tune it listening for that "four-stroking" sound (richen the H screw until the sound changes from smooth to a 'blubbering' of sorts.) and see how you like that.

Compare peak unloaded RPM's of all 3 methods.

You even could tune it for max loaded RPM (in the wood, might want an assisant for that) and then take a reading for peak unloaded RPM at that setting and see which of the 3 methods that comes closest to.

Hmmm. I might need to pick up a tach myself. Haven't had one since my dealership days...

 

[HittinSteel]

What is the max rpm for a 660? 9500 seems low

 

[thewoodlands]

HS,9500 is book for the 660. MM, thanks for the tips, I start with the 310 tomorrow night.

zap

 

[smokinj]

Heck my 880 was 11,500.

 

[thewoodlands]

Heck my 880 was 11,500.

Smokin, after reading this I decided to check the book again, it says 13,500 is the maximum permissible speed with bar & chain. Just above that on page 51 it says ISO 7293 : 9500 RPM
Idle Speed: 2500 RPM, I will stop by the shop in the morning to ask a few questions on what they recommend for rpm's.
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[HittinSteel]

Okay 9500 is max power in the cut....... warm the saw up and tune the high side to about 13,200 WOT, and then listen to make sure it's 4 stroking

 

[thewoodlands]

Since I'm a rookie what is four stroking?

zap

 

[HittinSteel]

I'm never good at explaining the sound, but it is basically the "burble" sound at WOT.... there is a wav file floating around on madsens saw site I believe and a nice example on the arboristsite if you do a search. If you have a good dealer, ask him to fire up a saw and let you hear it.

 

[thewoodlands]

I'm never good at explaining the sound, but it is basically the "burble" sound at WOT.... there is a wav file floating around on madsens saw site I believe and a nice example on the arboristsite if you do a search. If you have a good dealer, ask him to fire up a saw and let you hear it.

Found it, is that the noise when it flutters?
(broken link removed to http://www.madsens1.com/saw_carb_tune.htm)

zap

 

[HittinSteel]

Yes..... start at 12,500 with your saw and you should definitely hear it.....then lean the H (clockwise) some and hear the sound start to lessen. Your rpm's will increase. Have your tach going too and just don't go over 13,500 for very long (btw, the saw will not self destruct if you see 13,700-13,800) the max rpm of 13,500 is likely +/- 500.

Bet you'll settle around 13000-13200 where you can here it burble on top, but when you put the saw in wood the burble cleans up quickly (goes from "4 stroking" to "2 stroking") which is what you want.

 

[thewoodlands]

Yes..... start at 12,500 with your saw and you should definitely hear it.....then lean the H (clockwise) some and hear the sound start to lessen. Your rpm's will increase. Have your tach going too and just don't go over 13,500 for very long (btw, the saw will not self destruct if you see 13,700-13,800) the max rpm of 13,500 is likely +/- 500.

Bet you'll settle around 13000-13200 where you can here it burble on top, but when you put the saw in wood the burble cleans up quickly (goes from "4 stroking" to "2 stroking") which is what you want.

I stopped by the local stihl dealer this morning so I could confirm the rpm's, before I left I noticed this older chainsaw (090) must have weighed 30 lbs. He explained that a customer bought a new 880 so he took it in on trade, did a carb job on it an he will be testing it out this weekend. I did ask him how much for the saw, out of his mouth came it will go in my personal stock.
zap

 

[ScotO]

Found it, is that the noise when it flutters?
(broken link removed to http://www.madsens1.com/saw_carb_tune.htm)

zap

Zap, that is an excellent reference page for ANYONE trying to tune a saw. That "flutter" sound is exactly what you want, when you plunge into a round with the chain it will smooth out (under load). That guarantees your saw is getting lubrication/proper fuel mix under full throttle and full load. Great link, everyone out there that wants to know how to tune their saw by ear NEEDS to listen to these WAV files on that link. Thanks for sharing, bud......

 

[ScotO]

View attachment 64304 View attachment 64302
I stopped by the local stihl dealer this morning so I could confirm the rpm's, before I left I noticed this older chainsaw (090) must have weighed 30 lbs. He explained that a customer bought a new 880 so he took it in on trade, did a carb job on it an he will be testing it out this weekend. I did ask him how much for the saw, out of his mouth came it will go in my personal stock.
zap

Oh how I long for an 090 or Contra. 13hp of raw tree destroying mahem! Someday, boys...someday.....

 

[thewoodlands]

Yes..... start at 12,500 with your saw and you should definitely hear it.....then lean the H (clockwise) some and hear the sound start to lessen. Your rpm's will increase. Have your tach going too and just don't go over 13,500 for very long (btw, the saw will not self destruct if you see 13,700-13,800) the max rpm of 13,500 is likely +/- 500.

Bet you'll settle around 13000-13200 where you can here it burble on top, but when you put the saw in wood the burble cleans up quickly (goes from "4 stroking" to "2 stroking") which is what you want.

The 660 was at 14000 rpms I have it about 13200, the low idle is a tad over 2500. I'm checking all three saws again tomorrow. The manual for the 310 & 390 gave the idle speed at 2800 but I could not find the high rpm settings. Both the 310 & 390 read 13000 on the Tach.
zap

 

[smokinj]

The 660 was at 14000 rpms I have it about 13200, the low idle is a tad over 2500. I'm checking all three saws again tomorrow. The manual for the 310 & 390 gave the idle speed at 2800 but I could not find the high rpm settings. Both the 310 & 390 read 13000 on the Tach.
zapView attachment 64308View attachment 64309View attachment 64310

should be 12.5 to 13.5 range. If you want it perfect its with your ear. Every saw will be just a tad different. Even the exhaust guts loosing up will chang it from a stock number.

 

[thewoodlands]

Thanks Smokin, I had just emailed Stihl on the settings for the 310 & 390. I'm glad I checked the 660 before we started milling.

zap

 

[smokinj]

Thanks Smokin, I had just emailed Stihl on the settings for the 310 & 390. I'm glad I checked the 660 before we started milling.

zap

Some of those guys run a tac while milling. Seems kinda over the top but gives instant feed back.

 

[ScotO]

Altitute, humidity, temperature all can have an effect on RPM and tuning. All kinds of variables. That's why someday you'll use your ear to tune it and never need the tach. But that tach is nice to put your mind at ease.

 

[thewoodlands]

should be 12.5 to 13.5 range. If you want it perfect its with your ear. Every saw will be just a tad different. Even the exhaust guts loosing up will chang it from a stock number.

Just received the email from stihl on the high rpm settings for the 310 & 390, 13000 on both.
zap

 

[Thistle]

Oh how I long for an 090 or Contra. 13hp of raw tree destroying mahem! Someday, boys...someday.....

Oh you know it.The most powerful stock 1 man saw ever built. Even 1 of those legendary 1950's beasts like McCulloch 1225A or Disston 101 @15 or so HP were 2 man saws that weighed at least twice as much.

 

[MasterMech]

Oh you know it.The most powerful stock 1 man saw ever built. Even 1 of those legendary 1950's beasts like McCulloch 1225A or Disston 101 @15 or so HP were 2 man saws that weighed at least twice as much.

I can't imagine any of the old two man machines keeping pace with an 090 with modern cutting hardware on it. Probably the best thing about the 090 is that the cutting gear is still easily had and in production.