Dolmar Kaboom!

[PES+]

Let me claify that....try to never start a saw and just keep it pegged with out RPM variation for a full minute as this can indeed cause lubrication starving in certain areas. the throttle need to be blipped to distribure the lube oil. This is particularly true of a new saw or new piston and jug.

 

[troutfisher]

There is no reason to hold a saw wide open out of the cut more than 30 to 45 seconds at a time when tuning. If the saw is stock it should take a full minute at a time held wide open out of the cut provided it is not too lean from the start.

Wow, thats plenty of time to make adjustments. Just count "one thousand one, one thousand two," I would guess I hold the saw wide open 3-5 seconds at a time.

 

[PES+]

Wow, thats plenty of time to make adjustments. Just count "one thousand one, one thousand two," I would guess I hold the saw wide open 3-5 seconds at a time.

Me too...maybe 15 seconds if hunting for an intermittant problem...I used to make owners twinge sometimes holding it up for 20 seconds listening for detonation. Never lost one that way. Had a piston skirt crack while testing once and caught it before it came apart. The saw owner just stood there with his jaw hanging open when I pulled the jug and showed him the piston.

 

[THALL10326]

How long do you guys hold a saw at WOT, when adjusting the high speed? How long does it take to cause damage?

There's no need to hold the saw wide open for very long to get a full rpm reading on a tach. I ususally let the saw warm up, slowly rev it to 6-7,000 rpms and then gooch to wide open for just long enough to get my reading, which is only a few seconds at most. Thats providing you have a good tach that will read as fast as the saw puts out. Some tachs are slow catching up to rpms and I for one would not use them.

As to how long does it take to ruin a saw. They gave me and another boy a 036 and told us to go fry it. We ran it at 14,000 in the wood and had no problem. We turned it up to 15,000 and it still ran fine for several cuts. Finally we turned it up to 16,000 and ran it in the wood. Though it was losing power it kept on running. I finally took the saw and held in my hand wide open and in about 15 seconds it cut off on its own. We took it apart and it had the prettiest melted piston ya ever seen. It was when we were putting it back together that the instructor told us about the crank and bearings and that the rule was no more than 2 pistons and jugs to each crank due to over reving stress the bottom end had gone through.

Pest is correct about dirt injestion as well. A saw that injests dirt does not have to be over reving to ruin it. Concrete saws are a prime example of that.

 

[troutfisher]

There's no need to hold the saw wide open for very long to get a full rpm reading on a tach. I ususally let the saw warm up, slowly rev it to 6-7,000 rpms and then gooch to wide open for just long enough to get my reading, which is only a few seconds at most. Thats providing you have a good tach that will read as fast as the saw puts out. Some tachs are slow catching up to rpms and I for one would not use them.

As to how long does it take to ruin a saw. They gave me and another boy a 036 and told us to go fry it. We ran it at 14,000 in the wood and had no problem. We turned it up to 15,000 and it still ran fine for several cuts. Finally we turned it up to 16,000 and ran it in the wood. Though it was losing power it kept on running. I finally took the saw and held in my hand wide open and in about 15 seconds it cut off on its own. We took it apart and it had the prettiest melted piston ya ever seen. It was when we were putting it back together that the instructor told us about the crank and bearings and that the rule was no more than 2 pistons and jugs to each crank due to over reving stress the bottom end had gone through.

Pest is correct about dirt injestion as well. A saw that injests dirt does not have to be over reving to ruin it. Concrete saws are a prime example of that.

My tach is a pickup attached to my digital voltmeter. I agree, this setup uses a "sampling", It's not real time. How's the tach from Bailey's? I need a better setup.

 

[PES+]

Unless they changed the 36 cranks they are being a bit over cautious but it's their dime....Yah.....cut off saws are prone to dirt cause people never can figure out how to install the airfilters properly OR the clog the filter tight and take off the filter to "just cut that one little bit more"

crunch.....I never have been able to just do a piston a cylinder on a cut off the rock dust junks the whole crank as well...actually got in a fight with a contracter because I refused to re-use the crank. Him throwing cash at me and me throwing it back.....kind of funny...

 

[sawinredneck]

My tach is a pickup attached to my digital voltmeter. I agree, this setup uses a "sampling", It's not real time. How's the tach from Bailey's? I need a better setup.

I have a Mac setup like that, don't trust it above 13K!!!! Been there, done that!!

 

[PES+]

I can't find a digital tach with inductive pickup that goes higher than 14K I am back to analog which is faster but the units are fragile. Can't drop it once or it falls apart

 

[THALL10326]

My tach is a pickup attached to my digital voltmeter. I agree, this setup uses a "sampling", It's not real time. How's the tach from Bailey's? I need a better setup.

I use a old Stihl tach I've had for years now. It seems to stay right with the rpms all the way through. I rarely need more than just a few seconds to get a full rpm reading. I don't know what tachs Baileys offer but I do know the Stihl tachs work real fast and are very accurate. I think Ultra has one and he will attest its probly one of, if not the best, tach out there bar none.

 

[troutfisher]

I use a old Stihl tach I've had for years now. It seems to stay right with the rpms all the way through. I rarely need more than just a few seconds to get a full rpm reading. I don't know what tachs Baileys offer but I do know the Stihl tachs work real fast and are very accurate. I think Ultra has one and he will attest its probly one of, if not the best, tach out there bar none.

I'll call my stihl dealer monday. I'd rather have something that works, than save a couple bucks. I bought the tach I have for setting gov. speed on Briggs & Stratton. It works good for that.

 

[THALL10326]

Unless they changed the 36 cranks they are being a bit over cautious but it's their dime....Yah.....cut off saws are prone to dirt cause people never can figure out how to install the airfilters properly OR the clog the filter tight and take off the filter to "just cut that one little bit more"

crunch.....I never have been able to just do a piston a cylinder on a cut off the rock dust junks the whole crank as well...actually got in a fight with a contracter because I refused to re-use the crank. Him throwing cash at me and me throwing it back.....kind of funny...

I'm just repeating what the man told us Pest. He said that same 036 we burnt up had been overhauled countless times and that every third jug and piston he himself put a new crank and bearings in it. Beings he's right there at the factory I doult a crank and bearings is any big deal to him or Stihl. You should have seen the countless units of trimmers, saws, contrete saws and parts they use for the courses. That may be another reason the Gold course is only held at Va Beach though I'm just guessing on that.

True the concrete saws are a bit of a pain. Most want a new piston and cylinder and when you tell them the bearings are probly shot as well they get a strange look on their face. When they see the price of a crank along with what all is needed for a complete overhaul they tend to say the hell with that and buy a new saw. I never argue with that decision at all. I do say fliters are cheaper than saws, they wise up quick after buying that 2nd concrete saw.

 

[PES+]

The Sithl works well..the Echo does too....I have seen some now that do not have a replaceable battery and I won't consider something like that for myself.

I have not personally used one but several people whom I trust their judgement tell me the Tiny tach works well but you need to get the correct model which I can't recall at the moment. I'll look it up when I get a chance. I am considering oredering an Echo solar powered tach,,,cause I'm cheap

 

[B_Turner]

I am always suspicious of a saw with only a single bar nut.


Before my current Shindaiwa trimmer, I had a consumer Ryobi that ran too weak to be of use. So I said what the hell and tuned it for the most power. Ran pretty good for a couple hours before it seized. It was the only two hours that it was worth a toot, though, so it was worth it.

I typically tune my saws a little on the conservative side just because of all the variables in the real world (gas, etc.).

 

[PES+]

I have nightmares about Ryobi trimmers....you did the right thing IMHO

I am also in agreement with the single bar nut

 

[troutfisher]

I am always suspicious of a saw with only a single bar nut.


Before my current Shindaiwa trimmer, I had a consumer Ryobi that ran too weak to be of use. So I said what the hell and tuned it for the most power. Ran pretty good for a couple hours before it seized. It was the only two hours that it was worth a toot, though, so it was worth it.

I typically tune my saws a little on the conservative side just because of all the variables in the real world (gas, etc.).

We have a Stihl rototiller, kinda like a mantis, my wife has no mercy on that thing! tank after tank at wide open. I hear it running and feel sorry for the poor thing. It's two years old, and runs great!

 

[PES+]

We are also getting a rash of big end failures here that appear to be fuel related specific to certain gas stations....the importers of the saws are aware of it but no one seems to have an answer. These big ends fail but are spotlessly clean so it appears that we are getting some high concentrate ethanol blends at random and some of the premix oils are not carrying enough ester to keep the lube on the big end. We are going back to higher concentrations of castor base like it or not.

 

[sawinredneck]

We are also getting a rash of big end failures here that appear to be fuel related specific to certain gas stations....the importers of the saws are aware of it but no one seems to have an answer. These big ends fail but are spotlessly clean so it appears that we are getting some high concentrate ethanol blends at random and some of the premix oils are not carrying enough ester to keep the lube on the big end. We are going back to higher concentrations of castor base like it or not.

Not picking a fight here, you brought up a good point.

I think you are wrong on the oil base though, I see it more as moisture and ethanol in the fuel causing these failures, not the oils.

 

[PES+]

I am sure the saw makers would beg to differ despite what the oil guys claim. Yes it is the moisture that is the problem and the only solution is an ester (plant) base as no other oil has the ability to emulsify with water as quickly nor as completely. Smell all the latest offerings from the saw manufacturers on running and you can smell the increase in Castor.....nothing else smells like it

When you get water in the bearing it RESISTS the oil the worst being petroleum base.