How long can you keep the throttle wide open without load?

[Chucksta]

Yes, my question was about tuning the carb, so the assumption was that bar and chain were on.

As for the rest, someone more experienced will hopefully chime in, but my understanding is that you should retune when any of the following change: altitude, ambient temperature, oil/gas ratio, kind of oil, kind of gas, length and type of bar/chain. I mean this is probably overdoing it; I've definitely tuned for one bar length and merrily switched out to a longer bar and no issues. But if you're alaskan milling (like I am) I think you have to be a lot more careful. Crosscutting for firewood is a lot less load, so more forgiving.

You had two identical saws with different bars? Why not just have one saw and switch out the bars?

Back in the day, before I retired, I ran ( owned) a Landscaping company. I had about 20 saws, a few of which were the same, except for the bar(s). Small stuff? grab the 14 inch bar. Bigger stuff? Grab an identical saw with a 20 inch bar. Smaller bars always seem to cut quicker, due to less power loss pulling the chain.
Truthfully, I never re-tuned for a bar change.. It never crossed my mind to do so. It's also pretty flat where I am, not enough change in elevation to have to worry about altitude. I usually just pull the thingy over to the Winter setting in the carb, to prevent icing when it's cold outside.
As I always run the same oil and gas, at the same ratio, I seldom even think about re-tuning the carb. 91 Octane Ethanol free Premium, and 70 to 1 Amsoil Saber.
I Alaskan mill with an old school Stihl. I never changed the carb settings, when I purposed it for milling. Same fuel and mix as the rest of the crew. It truly didn't seem to mind at all. But I might think about putting in a touch more Saber into the tank.. A fouled plug is way cheaper than a new top end.

 

[SawPonder]

Question for you all (couldn't find the answer online): How long can you keep the throttle at full when tuning the H jet? My tach (proline solo) takes a few seconds, sometimes 3-5, to register the RPM reading. Is it OK to run WOT without load for, say, 5 seconds? What I've been doing is full throttle for few seconds, note RPM reading, wait for a few minutes, adjust carb by an eighth turn, recheck RPM, etc.

(Thank you all for excellent advice on the other threads I've started recently!)

Im know im late to the party and frankly this isnt really on topic but i thought the proline solo was supposed to be one of the fastest reading 2-cycle tach? 1/2 a second refresh time? Is that not true after all?

 

[anynameyouwish]

Im know im late to the party and frankly this isnt really on topic but i thought the proline solo was supposed to be one of the fastest reading 2-cycle tach? 1/2 a second refresh time? Is that not true after all?

No it's pretty fast as far as refresh rate goes. I've just found that it takes a few seconds to stabilize. I don't use the wires, just hold it close to the spark plug from outside the saw. Maybe that's why it takes some time to stabilize? It could also be that I start to hold it next to the spark plug before the RPMs are fully stabilized, so maybe what I should do is rev it fully, wait 2 seconds for the engine to get fully to max, and then use the tach. There are a lot of variations and I haven't experimented that much

The tach though does have a very fast refresh rate, and it's a nice little thing.

 

[Sidecarflip]

On subject:
"How long can you jeep the throttle wide open without ;load"

My response is How long can you keep your throttle floored in your vehicle in neutral and not blow the engine up?

Duh?

 

[bwalker]

On subject:
"How long can you jeep the throttle wide open without ;load"

My response is How long can you keep your throttle floored in your vehicle in neutral and not blow the engine up?

Duh?

Totally different engines.

 

[Breckinridge Elkins]

The no-contact feature is nice but lately I am using it with the alligator clip installed. One hand on the throttle, one for the screwdriver.

 

[HansFranz]

My response is How long can you keep your throttle floored in your vehicle in neutral and not blow the engine up? Duh?

Longer than you might think!

 

[Sidecarflip]

Totally different engines.

True, to a point and that point is they all share things like pistons, con rods, and crankshafts but exceeding the maximum working rpm for any length of time will destroy either a 4 stroke or a 2 stroke. Called centrifugal force and how it acts on moving parts that exceed their designed in limits.

Only time I ever free rev a saw is to check the RPM with an inductance tach and just for a few seconds and no more.

 

[bwalker]

True, to a point and that point is they all share things like pistons, con rods, and crankshafts but exceeding the maximum working rpm for any length of time will destroy either a 4 stroke or a 2 stroke. Called centrifugal force and how it acts on moving parts that exceed their designed in limits.

Only time I ever free rev a saw is to check the RPM with an inductance tach and just for a few seconds and no more.

Piston speeds are different bearing types are different, ring designs different, etc, etc.
Two stroke Karts will spin up to 20k rpm easily, 125 shifters 18k while loaded. And here we are worried about a unloaded low output chainsaw going poof when reved out to 14k UNLOADED..

 

[Sidecarflip]

All good with me, not here to argue anyway. I'm done.

 

[bwalker]

All good with me, not here to argue anyway. I'm done.

In other words don't let your facts get in the way of my superstitions.
And FWIW it's inertia that kills reciprocating motors. IE the piston and con rod acceleration and deceleration. This is commonly assessed by calculating piston speed.

 

[Sidecarflip]

In plain English, I get tired of jousting with people like you over what I know to be factual and I have way more thing to allot my time to so I won't bother. Linear piston speed in any internal combustion engine is just one mitigating factor and not the entire picture. Have a nic day, again, I'm done. Goodbye.

 

[bwalker]

In plain English, I get tired of jousting with people like you over what I know to be factual and I have way more thing to allot my time to so I won't bother. Linear piston speed in any internal combustion engine is just one mitigating factor and not the entire picture. Have a nic day, again, I'm done. Goodbye.

In plain English your basing your opinion on feelings and not facts.
Let's talk facts. The piston speeds are safe and with no load the engine will not be lean/hot, so what's going to damage the motor?

 

[Sidecarflip]

so what's going to damage the motor?

Your motor mouth. I have more important thins to do like manage the shop I own and do some TIG welding that is getting behind. Have a good day. Like I said previously, I'm done kibbitzing with no results.

 

[bwalker]

Your motor mouth. I have more important thins to do like manage the shop I own and do some TIG welding that is getting behind. Have a good day. Like I said previously, I'm done kibbitzing with no results.

Just admit. Your full of crap.

 

[Sidecarflip]

Just took a dump 5 minutes ago so no, I'm not. You are however.

 

[bwalker]

Just took a dump 5 minutes ago so no, I'm not. You are however.

Welding fumes must have cooked your brain.

 

[Husky77]

come on children your letting the forum down

 

[HansFranz]

Welding fumes must have cooked your brain.

...or he might have been huffing vaporized tungsten "tig welding aluminum on reverse polarity"

again

 

[muddy42]

Question for you all (couldn't find the answer online): How long can you keep the throttle at full when tuning the H jet? My tach (proline solo) takes a few seconds, sometimes 3-5, to register the RPM reading. Is it OK to run WOT without load for, say, 5 seconds? What I've been doing is full throttle for few seconds, note RPM reading, wait for a few minutes, adjust carb by an eighth turn, recheck RPM, etc.

(Thank you all for excellent advice on the other threads I've started recently!)

Returning to the OP, people advise buying a tach with a fast 0.5 second refresh rate for exactly this reason.