Starting Cold Chainsaws

[Kenskip1]

OK I hope that someone will be able to give me a good argument on why not to race a cold chainsaw. I am in a volunteer fire department in central Missouri.There are several full time members on 24/7. When ever the new shift arrives and does the check of all the powered equipment, the saws are on the list.We have I think 5 saws.A 455, 435,235,and a small Stihl. The mix is the trifuel so gasoline is not an issue.
The problem that I have is that these guys start the saws and run them at full throttle. This really pisses me off. I try and enplane that this is bad for the cylinder and piston however,,they persist on revving the engine.
All my saws start and are allowed to idle for a few minutes to allow the piston and cylinder to reach the same operating temperature gradually.In my train of thought this allows even distribution of heat before increasing the RPM.
Yes in certain situations this procedure can be omitted. Like needing to cut s hole in the side of a burning building.
Anyway I hope possibly a few saw engine builders will give me some free advise that these guys will understand. Thanks, Ken

 

[ironman_gq]

Piston heats up faster than the cylinder and expands which causes scuffing in minor cases or can seize the saw in bad cases.

 

[lone wolf]

Piston heats up faster than the cylinder and expands which causes scuffing in minor cases or can seize the saw in bad cases.

Especially in a new tight bore not a big problem in a well worn one. This is called a cold seize. It don't take long to warm up maybe a minute.

 

[82F100SWB]

A 4 corner or cold seize usually only happens when piston to wall clearances are tight and usually only in the first 30 seconds of runtime, first minute max. With an air cooled engine like a chainsaw, the cylinder is going to heat up quicker, making the possibility of this occourance lower than that of a liquid cooled snowmobile, and it is still relatively uncommon in sleds.

At sub freezing temps by the time the saw is running well enough that it will take full throttle the danger of a 4 corner seizure is most likely long past.
My father ran chainsaws for 40+ years, starting a saw and letting it idle to warm up just isn't a thing in his book, don't give it WOT right off of a cold start, but it's in the wood and working within a minute or two at max.

 

[grizz55chev]

A 4 corner or cold seize usually only happens when piston to wall clearances are tight and usually only in the first 30 seconds of runtime, first minute max. With an air cooled engine like a chainsaw, the cylinder is going to heat up quicker, making the possibility of this occourance lower than that of a liquid cooled snowmobile, and it is still relatively uncommon in sleds.

At sub freezing temps by the time the saw is running well enough that it will take full throttle the danger of a 4 corner seizure is most likely long past.
My father ran chainsaws for 40+ years, starting a saw and letting it idle to warm up just isn't a thing in his book, don't give it WOT right off of a cold start, but it's in the wood and working within a minute or two at max.

As a side note, if you have to piss rev your saw to keep it running when cold it ain't tuned right or you have other issues.

 

[user 122190]

Excessive wear as parts are not heat expanded to proper operating size. As said, parts expand at different rates further complicating the full running wear of a machine.

But the real problem is the guys don't own the machines so don't have a vested interest in the life of the saws.

 

[HarleyT]

I don't think that it is much of a problem, just a bunch of theories based on what their Grandpa told them.

 

[Sleepy]

There used to be a guy where I worked, who every morning when he got off, (worked third) would fire his 600cc crotch rocket, and immediately put it on the rev limiter.
I learned right then, to some people an engine is nothing but a noise maker, and the more they can make, the more they like it.
I'm of the mindset that everything needs a little while to get up to temperature so things fit like they should, and have never had engine problems with anything other than normal wear.

 

[merc_man]

I agree that they should be fired up and let idle for a few minuts then i gradually roll on the throttle while cutting smaller stuff.
Although in your case. In the event of an emergency. I would be fire them up and wide open if newdw. But not for testing to make sure they run .

Sent from my SM-J320W8 using Tapatalk

 

[ChoppyChoppy]

What temp is "cold"? I'd imagine your fire trucks are parked indoors in a heated building?

I'll let my saw run maybe 10-15 secs before cutting when the saw is well below zero, but if it's warm (like maybe 20* or hotter) I don't do anything special.

Letting run several minutes isn't needed. Not that it will hurt anything, but they say anymore not to do that to cars even.

 

[Gypo Logger]

I really dont think doing a warm up makes any difference. A cold saw suffers from incomplete combustion, therefore lots of residual lube.
If the piss revers insist on goosing a cold saw and it bothers the op, he should tell them to choke the saw off when they finish sawing.

 

[Kenskip1]

Gypo, I have a picture of you that I just May post. Back at Jokers GTG.

 

[HarleyT]

Make sure that he has clothes on!!!

 

[1Alpha1]

Cold racing a saw is no different than jumping in your family car or truck, starting it up and flooring the gas pedal at the same time.

Ask them if that's the way they treat their own cars when it's frigging cold out?

Do they start the fire trucks that way as well? Better not be. I'm a US taxpayer and I pay for those trucks.

 

[Gypo Logger]

Gypo, I have a picture of you that I just May post. Back at Jokers GTG.

Lol, you mean the lap monkey pic? Post it up.

 

[Gypo Logger]

I don't think that it is much of a problem, just a bunch of theories based on what their Grandpa told them.

You mean alternative facts?

 

[Kenskip1]

Look at my previous post

 

[Gypo Logger]

View attachment 554956 Gypo, I have a picture of you that I just May post. Back at Jokers GTG.

 

[HarleyT]

Cold racing a saw is no different than jumping in your family car or truck, starting it up and flooring the gas pedal at the same time.

Ask them if that's the way they treat their own cars when it's frigging cold out?

Do they start the fire trucks that way as well? Better not be. I'm a US taxpayer and I pay for those trucks.

So a chainsaw is the same as a car or fire truck?

 

[82F100SWB]

Last I checked there was no oil sump or pump and lube went in with the fuel.