John Deere 855/856 hard starting

[Harry in Ky]

Fuel de-priming? I'm not sure that's a word, but I don't think that's the case here either. Did you change the filter BEFORE or after you attempted to start it this last time? Personally, when given the choice I never change fuel filters on a cold engine. I always start and run it for a few minutes, shut it off and then change filters. Engines always seem to start better the second time around and the system is all primed, injector lines are charged up, and all that.

If it were actually "de-priming", the first attempt to start it would produce no smoke at all, or just a few puffs then go away entirely before coming back and eventually the engine starts. I doubt that's the case here, or is it?

As for bleeding the injectors, my experience has been where that only becomes necessary when the engine won't start at all due to lack of fuel in the injector lines. (for whatever reason) If it starts and runs at all, then bleeding injectors is USUALLY not needed unless there is a pump problem. That's not a typical concern with this style pump. I'm not a pump specialist so that's a personal observation only.

 

[D&D]

Well, I just tried it again and it took 4 tries to start it and lots of black smoke. But once it had been running, I could turn it off and on at will no problem and the smoke seemed normal. If I wait a few hours, it probably will be hard to start again with the black smoke.

Does this sound like fuel de-priming to you? Again, I changed the fuel filter....so is it cranking a lot to pull fuel back into the system? I just bled it at the fuel bowl and pump again but still have not tried bleeding at the injectors as the instructions seem a bit unclear to me.

How cold is it where you park the tractor?

 

[gstrom99]

Welcome. I bump the throttle up a little, whenever I start mine, especially when cold starting. If I leave it at base idle, it is not happy. I've always had some black smoke at startup. Once it (yours) is/has been running, there's really no point in bleeding it more - unless there is a cracked/leaking line (filter seal?) somewhere letting air in.

 

[MTGreen]

I'm leaning towards it not being a fuel problem. Black smoke means too much fuel.
Since your preheater works, the tractor runs fine once it starts so that rules out injection pump timing or gross injection pump problems, that leaves compression or not spinning fast enough while cranking.

From my perspective you should adjust the valves -always makes a noticable difference with starting easier, starts at lower rpm, and quiets the engine down as well

 

[Hillwalker]

@Harry - I changed the fuel filter in September and this problem just started in November/December
@D&D - It is 32 degrees at night and 55 degrees in the day time here
@grstrom - Yes, I've tried multiple throttle positions
@MTGreen - It does seem like it is not spinning fast enough, that's why I changed the battery. Even on the fourth try, have to use the starter to help it spin faster (Hold it for too long, frankly). Is adjusting the valves something that a layperson can do with the manual?

 

[MTGreen]

Starter speed is voltage dependent and assuming a good battery voltage is resistance dependent. You could try to minimize resistance by wire brushing both ends of both battery terminals and reconnecting and verifying that you have a solid ground to your starter by running an extra ground cable to your starter mounting bolt (not the + battery connection lug).

Adjusting the valves is simple with feeler gauges and a wrench and socket set.

 

[Hillwalker]

Got it, I will give both of those things a try. One more question: If the valves are out of adjustment, is the thinking that it would be creating too much compression, which is therefore slowing down the starting speed?

 

[D&D]

Got it, I will give both of those things a try. One more question: If the valves are out of adjustment, is the thinking that it would be creating too much compression, which is therefore slowing down the starting speed?

Page 2-119

http://www.wfmfiles.com/download/manuals/CTM3.pdf

 

[D&D]

@Harry - I changed the fuel filter in September and this problem just started in November/December
@D&D - It is 32 degrees at night and 55 degrees in the day time here
@grstrom - Yes, I've tried multiple throttle positions
@MTGreen - It does seem like it is not spinning fast enough, that's why I changed the battery. Even on the fourth try, have to use the starter to help it spin faster (Hold it for too long, frankly). Is adjusting the valves something that a layperson can do with the manual?

Can you park it someplace warm or use a heater before first start?

 

[hosspuller]

Got it, I will give both of those things a try. One more question: If the valves are out of adjustment, is the thinking that it would be creating too much compression, which is therefore slowing down the starting speed?

Out of spec Valves would mean losing compression. Leading to hard cold starting.