Jinma 284 very slow startup when cold

[TimP82]

Hello everyone.
The problem I'm noticing this winter is that when I start the tractor when temperatures are cold (less than 40 degrees F), when it starts the idle is super low. Like so low that I can watch the fan belt slowly turning around the pulleys (maybe 100 rpms?). It will do this for maybe 30 seconds or so, then the rpms will start to come up to where ever I have the throttle set at. It only does this during 1st cold startup, after that it starts and runs great. There's fresh diesel in the tank, newer fuel filter, valve lash checked and set last spring but I'm at a loss. I turn the key to warm the glowplugs for about 30-45 seconds before starting, watching the amp meter to ensure they are working.

I don't remember the tractor doing this last winter and when its chuging along at the slower rpms, its smoking dark smoke out the exhaust.

Does anyone have any ideas?

 

[Bob Rooks]

Three possibilities:

1) Air cleaner is fouled, barely enough air for combustion (black smoke).

2) Too heavy of viscosity in fuel injection pump, or no oil at all. Use same oil as in engine (15w-40) Governor cannot respond to speed setting (there is no mechanical linkage between the hand throttle and the rack.

3) Dribbling injectors. Too much fuel for the amount of available air (Not unlike symptom #1).

 

[Roadworthy]

By all means check your air filter but also check that no critters have built nests out of the weather in your air intake.

 

[TTTTTT]

I'm in a cold climate. Similar issues awhile back. I discovered have manually throttle full open when cranking and then backing off as the the fuel gets flowing and the idle smooths out. Discovered later the manual says to do it on cold starts. Remember diesel viscosity, is a little less in cold. I always use an additive in my fuel also.

 

[TimP82]

Thanks for all the advise everyone. I will certainly check the air filter and I'm now wondering about the injector pump oil. I change it every year when I do the engine oil change. I use Rotella 15w-40 for the engine but I use ISO 100 for the injector pump, which is close to a straight 30w oil. I will certainly try changing that to the lighter engine oil.

Also when I start it, I always set the throttle to full and as it starts, I back it down once it hits about 1000 rpm's.

 

[Smalljobs]

I have two Wolverine pads. One is under the engine sump and the other is under the hydraulic sump. They've been on for years with no issues. Starts like summertime and hydraulics work right away with no warm up.

 

[RonMar]

its a diesel... A simple one, it does not have cold idle. I have a coolant heater for when it gets cold. Plug it in 10-20 minutes before I need the tractor, warm start every time I don't do the full throttle start, but I do bump the throttle to where the engine is at about 1200 RPM when I shutdown. This insures enough fuel delivery at startup to get a colder or weaker cylinder firing immediately. As soon as it catches, I SET THE IDLE by pulling it back to 900. Once it is warmed up it will idle at 900 with the throttle all the way down. You also want to get that idle up as it can get you low oil pressure and added bearing wear as the pump is delivering low volume at low idle.