Half throttle for starting???

[Doc_Bob]

I was reading my owners manual for my TN70A. I learned I was making a mistake in how I start my TN!!!!!! I just started the engine. Starts every time. Temps have been above 60 degrees. Now, the owner’s manual says I should have the throttle lever positioned at halfway. Why??? I assume the motor would race when it starts. Do I really want it to race for even a second when cold? What does putting the throttle lever at half way position do to help start the engine?? Have I harmed the engine by having the throttle lever set at idle when I start it?
Bob

 

[Hooked_on_HP]

Bob you start your tractor like I start mine. Some owners manuals even say 3/4 throttle. My thought is that if it starts fine at idle thats where to start it. I maintain a fleet of trucks and if I caught a driver starting a truck at 1/2 throttle he would get his butt chewed. When I start any motor I let it idle for a few minutes to let the oil circulate to all the parts before putting a load on it.
Bill

 

[ovrszd]

Bob you start your tractor like I start mine. Some owners manuals even say 3/4 throttle. My thought is that if it starts fine at idle thats where to start it. I maintain a fleet of trucks and if I caught a driver starting a truck at 1/2 throttle he would get his butt chewed. When I start any motor I let it idle for a few minutes to let the oil circulate to all the parts before putting a load on it.
Bill

AMEN!!! I cringe when I see people start an engine and immediately rev it up!!! OUCH!!! Start every engine and let it idle for at least 15 seconds before touching the throttle, this includes your car!!! If you have ever started an OHV engine with the valve cover off you would see the importance of this. It's at least 15 seconds before oil appears on the valvetrain.

My new Deere grader is computer operated, it automatically goes into fast idle when started which raises the idle speed about 150 rpms. I can't even get used to that!!!!

You don't jump out of bed and run to the bathroom do you??? Okay,,, bad example,,, maybe sometimes you do....

 

[HGM]

I agree with the other guys.. You would surely see this more than I do, but does it require more throttle to start it in the winter? I would think that whatever you need to start it is fine, but just what you need because of the oil starvation issue..

 

[Youare]

My Kubota starts fine at the lowest throttle setting at any temperature. Even at that setting the engine races for a few seconds in cold weather, seems to be related to the length of time the glow plugs are energized before starting.

The one thing I do not like when starting my car or truck is the computer puts the engine at fast idle as soon as it starts. I think I read somewhere that 90 percent of engine wear takes place in the first 30 seconds after starting. Once an engine has not run for 4 or 5 hours most of the oil has drained out of the critical lubrication areas and takes a few seconds to get pumped back in.

If the engine is has been off for just a little while there is still a film of oil lubricating the bearings so there in not as much wear on start up. Maybe there should be a small electric oil pump that circulates oil for a few seconds before starting a cold engine.

Randy

 

[Zoombah]

Doc_Bob,

My TN65 starts just fine at low idle. Other than cause unnecessary engine wear I cannot think of anything that a half-throttle start up would do for the engine.

The computer controlled diesel in my truck always starts at low idle. On cold mornings and AFTER a couple minutes of low idle it automatically idles itself up to about 1,000 rpm to speed warm-up time. Have always thought that feature was pretty slick.

 

[HGM]

The one thing I do not like when starting my car or truck is the computer puts the engine at fast idle as soon as it starts. Randy

Honestly, carburators did that too.. Thats why you patted the accellerator when you got in the car, to give it a squirt and set the choke..

Really, I think we make too big of deal out of this sometimes.. If a car/truck/tractor can run over 200,000mi (or equivilant hrs in a tractor) we've done pretty good and come a long way over the early years when an ovehaul was needed before 100k.. Personally, I wouldnt worry too much about it and just start it like I saw fit. I dont think your doing anything wrong starting at an idle.. IMO..

 

[ronjhall]

Now, the owner’s manual says I should have the throttle lever positioned at halfway. Why??? I assume the motor would race when it starts. Do I really want it to race for even a second when cold? What does putting the throttle lever at half way position do to help start the engine?? Have I harmed the engine by having the throttle lever set at idle when I start it?
Bob

My Kubota B2910 says the same thing about 1/2 throttle. I have tired to start the engine at that setting. It starts just as quickly as it did at idle setting. But I cannot believe that this is a good thing. I start engine at idle. After running for a couple of minutes I move throttle up to get engine running at 1500 RPM's until it's warmed up.
It has worked OK for over 6 years now.

 

[Soundguy]

When i shut my (diesel ) tractors down, i reduce the idle to 800-1000 for cooldown. I leave it set at that for when i start it the next time. Has always worked for me.

Now.. I once heard someone tell me that the rack on a diesel may be full open at start due to the governor.. however.. it seems that as soon as the engine is started that reguardless of what the initial rack setting was.. that it would immediatly jump to match the throttle setting.. thus.. if you start at low idle.. it starts.. then adjusts.. or if at high idle.. it starts then idles up.. etc.

I am not a diesel mechanic ( I'm not a mechanic at all! ).. so i can't verify that info.. etc.

Soundguy

I was reading my owners manual for my TN70A. I learned I was making a mistake in how I start my TN!!!!!! I just started the engine. Starts every time. Temps have been above 60 degrees. Now, the owner’s manual says I should have the throttle lever positioned at halfway. Why??? I assume the motor would race when it starts. Do I really want it to race for even a second when cold? What does putting the throttle lever at half way position do to help start the engine?? Have I harmed the engine by having the throttle lever set at idle when I start it?
Bob

 

[Doc_Bob]

Now.. I once heard someone tell me that the rack on a diesel may be full open at start due to the governor.. however.. it seems that as soon as the engine is started that reguardless of what the initial rack setting was.. that it would immediatly jump to match the throttle setting.. thus.. if you start at low idle.. it starts.. then adjusts.. or if at high idle.. it starts then idles up.. etc.

What is a "rack" on a diesel?
Bob