JD 855 starting problem

[Jay Cadillac]

My low-hours 855 (1997 model, no glow plugs) has developed a pain-in-the-ass cold-starting problem. Even on non-cold days it will not start unless I (1) plug in the freeze plug heater for an hour or more and (2) place a 100-watt light bulb in the engine compartment for at least an hour. (The bulb is placed right over that housing on top of engine that apparently has something in it that heats up to make starting easier, whatever it's called.) I cleaned, with my air compressor, the relay (mounted on the firewall) going to that housing and that seemed to help for awhile, but now it's back to hard starting. Is that housing supposed to get super-hot, does anyone know? Would replacing the (expensive) relay perhaps fix the problem? When the light bulb is on long enough the dashboard light will not come on at all and the engine usually starts right up. When the dashboard light does come on (usually for 5-10 seconds or more) it will not start.

 

[Roadworthy]

Are you SURE your tractor has no glow plugs? I believe most of the Japanese engines in compact tractors from that era did have them. Your engine is a Yanmar, by the way. Look for an owner's manual or a schematic diagram. TractorData.com John Deere 855 tractor information

 

[wpatz]

I have a 2514 that had a starting problem under 35 degrees, but cleaned connections on glow plugs , now starts good, i am almost positive you have glow plugs , if you have a problem with them re-wire with a momentary switch ,30amp, made a difference on my CAT,,,, good luck and GOD Bless , Willie (central Wisconsin)

 

[arrow]

There are NO glow plugs on this engine. It does have an air inlet heater or "pre combustion chamber". It is this heater that may be at fault.

 

[Jerry/MT]

My low-hours 855 (1997 model, no glow plugs) has developed a pain-in-the-ass cold-starting problem. Even on non-cold days it will not start unless I (1) plug in the freeze plug heater for an hour or more and (2) place a 100-watt light bulb in the engine compartment for at least an hour. (The bulb is placed right over that housing on top of engine that apparently has something in it that heats up to make starting easier, whatever it's called.) I cleaned, with my air compressor, the relay (mounted on the firewall) going to that housing and that seemed to help for awhile, but now it's back to hard starting. Is that housing supposed to get super-hot, does anyone know? Would replacing the (expensive) relay perhaps fix the problem? When the light bulb is on long enough the dashboard light will not come on at all and the engine usually starts right up. When the dashboard light does come on (usually for 5-10 seconds or more) it will not start.

Get yourself an owners manual and learn what type of cold assist starting aids you have on your tractor.

You mentioned the block heater which warms up the coolant and you shouldn't need that to start unless it's below about 40° F.

You say "(The bulb is placed right over that housing on top of engine that apparently has something in it that heats up to make starting easier, whatever it's called.) I cleaned, with my air compressor, the relay (mounted on the firewall) going to that housing and that seemed to help for awhile, but now it's back to hard starting." Is this on the intake manifold? If it is it might b a grid heater to pre heat the air going into the engine at start up. Usually these run off a certain position of the key switch and have to be activated for a certain time period to be effective. The relay maybe what powers this device. Check for voltage when you try to start.

Long distance diagnosis of these types of issue is difficult when the owner can't describe the system he's talking about.

The relay you speak of may also be for the glow plugs which most of these small compacts use as starting aids. Is there some wires going to the cylinders near the injectors and attached to a spark plug type device on the cylinder head? Do these wires run to the relay? If so then that relay is the glow plug relay and it my be activated by a separate switch or by a separate position of the key switch. Check for voltage at the terminals of the glow plugs when you try to start. Glow plugs can fail so that may be your problem if you have voltage at the plugs.

I do know if this helps you but not being familiar with you specific tractor and your inability to describe the systems makes it hard to be more helpful.

 

[arrow]

" glow plugs which most of these small compacts use as starting aids".

Not this one.
It uses a "heater" that warms the air inlet. My JD 750, which also had a Yanmar engine, used the same technique.

 

[CoyPatton]

Are you SURE your tractor has no glow plugs? I believe most of the Japanese engines in compact tractors from that era did have them. Your engine is a Yanmar, by the way. Look for an owner's manual or a schematic diagram. TractorData.com John Deere 855 tractor information

Yes his 855 was built by Yanmar to JD specs. Yanmar of that era used what they called a thermostart (TS) system. To try to make it simple it drips fuel into the intake housing and ignites the fuel using a spark plug like thermostarter.
Typically there is a key spot that is labeled TS that sends power to this and it is also powered during starting position of the key.
I would guess the 855 has this system but not 100% positive with looking at the tractor.
It should get warm to touch if working but not really hot hot.
I know Hoye Tractor in TX carries some items for the JD Yanmar tractors, what and how much for 855 I do not know.

And there is a fuel supply from a small plastic bottle toward the front and above the engine as well as an electric supply to the thermostart.

 

[joecdeere]

855 does not really have a thermo-start, as posted above it has a heating grid to pre-heat intake air. It is mounted to the top of the throat of the intake, it is controlled by a module that reads the outside air temperature and it decides if heating is needed