Should I idle or turn it off?

YellowHammer · January 22, 2013, 12:23:29 AM

I have found myself letting my LT40 idle when I'm stacking boards or moving cants, or doing things in the day to day business of sawing. It keeps my battery charged, engine warmed up, saves the starter, and cuts down on the reboot cycles of my Accuset. So other the just putting hours on the engine, is this doing any other harm? Am I prematurely wearing the main drive belt? Am I setting myself up for some sort of bearing issue? Nothings engaged, blades not turning, just letting the diesel idle. Or should I be turning it off whenever it's not in the wood?
Thanks
YH

ladylake · January 22, 2013, 04:27:13 AM

It depends how long , I'd turn mine off if more tham 10 - 15 minutes. Steve

dgdrls · January 22, 2013, 05:40:05 AM

I am of the thought that if the oil system on the motor is pressurized no big deal,
if its a splash system, I would not idle for very long. What engine is on it and what does
the man' suggest?

DGDrls

Al_Smith · January 22, 2013, 06:41:53 AM

It should be a pressurized system being a diesel I'd think .

What however should make a difference if it were a splasher ?

Magicman · January 22, 2013, 07:09:26 AM

As a general rule, mine is shut down for lunch.

Tronvik · January 22, 2013, 07:23:16 AM

I turn mine off if it has to idle more than 10-15 min. Just to let the air cooled engine cool down. I know it can be debated that the engine will cool better when running. My onan 20 will drink the fuel and if I turn it off I can run all day on a 3 gal tank.

drobertson · January 22, 2013, 07:48:13 AM

I don't know if you should or have to, I have a friend that worked the riggs out west, he said on the cold snaps they would run their diesels contiunually. I idle mine while stacking, but its like less than thirty secs. I shut down when reloading the deck. Seems like something or someone shows up around this time. I see no need to run any extra fuel than necessary.

Al_Smith · January 22, 2013, 08:00:16 AM

Well I suppose like most it depends on how you look at things .I had a chief engineman in the navy once tell me you wear the engine out more by starting it more so than running it .

Chuck White · January 22, 2013, 08:02:29 AM

If I'm away from the controls more than 10 minutes or so, I shut down.

YellowHammer · January 22, 2013, 09:11:54 AM

My engine is a 34 Yanmar, liquid cooled diesel. I usually start it in the morning, shut it down at lunch then saw until dark. I usually just keep it running unless I have to leave the area. It hardly burns fuel at idle and a tank lasts me all day if I idle or not.
When I'm idling, am I also wearing a flat spot on my drive belt since the pully is spinning but the belt is slack or has anybody noticed?

YH

thurlow · January 22, 2013, 09:39:38 AM

Been dealing with diesel engines (Alice Chambers ;D, IH, JD, M-F) since about 1958; if we let any of 'em idle for more than a couple of minutes, we always revved 'em up to about 1500 rpm or so; it's been my experience that letting 'em idle leads to problems. Various mechanics have told me the same thing.............

Al_Smith · January 22, 2013, 09:48:07 AM

Well then you have those diesel switchers in the rail yards .I'm not sure if the ever turn them off .

sawguy21 · January 22, 2013, 09:48:41 AM

That is a good idea, keeps cooling air and anti freeze moving. Fuel is also more completely burnt.

rmack · January 22, 2013, 10:16:47 AM

Quote from: YellowHammer on January 22, 2013, 09:11:54 AM
My engine is a 34 Yanmar, liquid cooled diesel. I usually start it in the morning, shut it down at lunch then saw until dark. I usually just keep it running unless I have to leave the area. It hardly burns fuel at idle and a tank lasts me all day if I idle or not.
When I'm idling, am I also wearing a flat spot on my drive belt since the pully is spinning but the belt is slack or has anybody noticed?

YH

I have the Yanmar too, mine is rated 35hp, not sure if it's the same one. anyway, mine idles very rough, such that it sets up a harmonic with the head that gets the debarker bouncing like nobody's business when the engine is idling. As well, the blade sprocket covers and anything else on the machine that can rattle does so at idle. Do you have the same problem?

I have bought a digital tachometer and plan to experiment with changing idle speed to get rid of the harmonic when I get the mill out of storage in the spring. I'm hoping it won't take too much to move it out of the problem range.

couldn't be more impressed about fuel consumption though. 8)

pineywoods · January 22, 2013, 10:29:32 AM

Quote from: YellowHammer on January 22, 2013, 09:11:54 AM

When I'm idling, am I also wearing a flat spot on my drive belt since the pully is spinning but the belt is slack or has anybody noticed?

YH

If you are wearing a flat spot on the drive belt, then something ain't quite right. The upper and lower belt guards squeeze the loose belt down in an oval shape, so it barely touches the pulley, if at all. Those guards are more than just a safety cover, they are an integral part of the drive train. I found out the hard way when I swapped out the motor on my mill for a different type. The crank pulley on the new motor is about an inch lower than the original. I went through drive belts like crazy until I finally figured out that the covers are more than osha requirements. Some minor modifications fixed that problem..

ladylake · January 22, 2013, 10:35:43 AM

Quote from: rmack on January 22, 2013, 10:16:47 AM
Quote from: YellowHammer on January 22, 2013, 09:11:54 AM
My engine is a 34 Yanmar, liquid cooled diesel. I usually start it in the morning, shut it down at lunch then saw until dark. I usually just keep it running unless I have to leave the area. It hardly burns fuel at idle and a tank lasts me all day if I idle or not.
When I'm idling, am I also wearing a flat spot on my drive belt since the pully is spinning but the belt is slack or has anybody noticed?

YH

I have the Yanmar too, mine is rated 35hp, not sure if it's the same one. anyway, mine idles very rough, such that it sets up a harmonic with the head that gets the debarker bouncing like nobody's business when the engine is idling. As well, the blade sprocket covers and anything else on the machine that can rattle does so at idle. Do you have the same problem?

I have bought a digital tachometer and plan to experiment with changing idle speed to get rid of the harmonic when I get the mill out of storage in the spring. I'm hoping it won't take too much to move it out of the problem range.

couldn't be more impressed about fuel consumption though. 8)

Just speed it up some , no need to tach it. My 3 cyl Isuzu is rough also when idleing to slow. 1/2 gph working hard. Steve

Qweaver · January 22, 2013, 10:40:46 AM

I usually leave my engine idle thru the whole log cutting but turn it off while loading for re-saw and a new log. Mainly just for the quiet more than anything.

CalebL · January 22, 2013, 10:45:52 AM

I have the 34hp Cat and I leave it running unless I'm eating lunch.

YellowHammer · January 22, 2013, 11:10:56 AM

Lots of very useful feedback, thanks.

You are right, its a 35 hp Yanmar, and it idles as smooth as any diesel engine I've been around. No shaking or rattling of the mill either. I don't have a tach so don't know what speed it is, but it "sounds" right. Certainly not shaking the debarker or anything like that.

I didn't realize that the belt guards give the belt clearance off the main drive pulley to protect from wear. Pretty slick. I havent had have any premature belt failures so it sounds like its set correctly.

pineywoods · January 22, 2013, 11:19:30 AM

Shutting down a hot engine is not a good idea. Idle for a short time to allow things to cool down a bit. Especially with air cooled engines, when you shut down, there is no more cooling air flow, so it just sits there and cooks itself. Oil starts to break down at around 300 deg F. and turns into black coke, not good for the moving parts.

rmack · January 22, 2013, 01:10:24 PM

Quote from: YellowHammer on January 22, 2013, 11:10:56 AM
Lots of very useful feedback, thanks.

You are right, its a 35 hp Yanmar, and it idles as smooth as any diesel engine I've been around. No shaking or rattling of the mill either. I don't have a tach so don't know what speed it is, but it "sounds" right. Certainly not shaking the debarker or anything like that.

I didn't realize that the belt guards give the belt clearance off the main drive pulley to protect from wear. Pretty slick. I havent had have any premature belt failures so it sounds like its set correctly.

did you get the belt tensioning tool, and instruction on how to use it when you bought the mill?

dgdrls · January 22, 2013, 06:22:32 PM

Quote from: Al_Smith on January 22, 2013, 06:41:53 AM
It should be a pressurized system being a diesel I'd think .

What however should make a difference if it were a splasher ?

Yup I missed it was a diesel.
More my thoughts that splash air cooled motors don't splash or cool as well at low RPM's

Would think that little diesel will pop along just fine at an extended idle.
Just make sure the radiator is clear.

DGDrls