How long do you let her "warm up"?

[dynasim]

Chuck,

The HST is not heated, not an integral part of the engine, nor does it have a temperature controller(it typically has a cooler, but the heat removal is not controlled). I wasn't talking about the engine, which will have the same temperature in florida or alaska, because it has a thermostat.

Chris

 

[Z-Michigan]

The manual for my 790 says to open the (hand) throttle completely, then start the tractor.
That sure seems like it would be tough on the engine, so I've never done started the tractor like that. I start with the throttle "closed", then increase the RPM to 1200-1500 once the engine catches.

The manual for my Deere 5105 said to open the throttle 1/3, and that the engine might not even start if I didn't do that. I did that ONCE, discovered that the engine came to life and raced to 2000rpm, I backed off the throttle. Now I open the throttle just a tiny bit and hope to see 1000-1200rpms after startup. Dealer told me not to let a new diesel idle at lowest idle due to problem called "wet stack" - unburned fuel collects in exhaust system and makes nasty sludge that can't be removed except by operating dozens of hours at full power.

Back to the main topic... I personally hop on, start the tractor, then hop off and do a quick walk-around inspection. I get back on, put seatbelt on, raise 3ph and FEL, move to a very low gear and start slowly moving where I'm going to be working. If temp is below 25 F. I may let it idle a bit more, but otherwise no. Temp gauge will not start moving for a couple minutes whether I let it idle or use it. Dealer told me not to let it idle at lowest rpm due to "wet stack" mentioned above, but to idle at significantly higher rpms, maybe 1500 or so. I don't think there's any difference from the engine's point of view in idling at 1500 vs. moving in 2nd or 3rd gear at 1500rpm (which is very light load).

I have two diesel vehicles - pickup and Jeep CRD. Neither one will warm up from idling very quickly - much slower than gasoline engines. The Dodge truck in particular (Cummins engine) takes over 5 minutes to show any temp movement if just idling, and the owner's manual says not to idle for more than 5 minutes. Go figure. With the Cummins I will typically idle for 10-30 seconds in normal temps, and maybe up to 5 minutes in temps below 25 F., but either way it won't be warmed up til driving several miles. The Jeep CRD warms up a bit faster but still doesn't get up to operating temp unless driven. I let it idle 10-20 seconds typically, partly to let automatic transmission get fluid circulating.

Tractor engines are made to run mostly at full power, so are overbuilt compared even to truck engines. After idling it long enough to get oil circulating, I personally don't think there is much benefit to letting it warm up more vs. doing very light work (moving in low gears, not anything ground engaging). On the other hand I am new to hydraulics and they do seem to take more time to warm up and get fluid circulating, so perhaps 1-2 minutes of idling is good for the hydraulic system (or longer in cold weather).

 

[RobJ]

The manual for my Deere 5105 said to open the throttle 1/3, and that the engine might not even start if I didn't do that. I did that ONCE, discovered that the engine came to life and raced to 2000rpm, I backed off the throttle. Now I open the throttle just a tiny bit and hope to see 1000-1200rpms after startup.

My guess is the "open throttle" at startup is just to help keep the engine up at some speed. Another guess is its for an area that isn't 80 degrees at 8:00am. The governor moves the throttle to wide open when the engine is off. As soon as it moves the weights pull it back to the selector position (idle). Also fun when the fuel rack sticks....at WOT...a runnaway.

Tractor engines are made to run mostly at full power, so are overbuilt compared even to truck engines.

Diesel engines are really the same. Our little Kubota/Deere engines are the best examples. You might find this engine in a generator set, stationary power unit, water pump, etc. The only difference is the fuel pump settings. They rate for continuous load or imtemitting load. On the gen sets I use to put together the engines came from the factory rated for something like 2200rpm, continuous load, we would have the pumps reset to 1800 rpm (for 60hz, 1500 for 50hz (if I recall...going overseas), the pump shop would also change out the governor weights. Lighter I think for more responsiveness. I didn't work directly on the pumps, we sent them out to M&D.

Rob