Hard to start after running a while

[Patrick C Potter]

I have a John deer 300B backhoe ever since the motor was rebuilt it is very hard to start after it?s been used a while, I do know for certain the #2 injector is not letting fuel through alternator is charging and a new 950 CCA commercial battery. When it?s cold or has cooled off for a while (about an hour) it spins fast with near immediate start

 

[Jim.ME]

Does it crank faster if you rapidly rock the steering wheel?

Where is the battery ground cable attached to the tractor?

How old is the starter? It could be heat soaking and have a higher draw when hot along with normal wear.

You are running it with known a dead injector? Why not fix that before that causes other issues?

 

[David G]

Others have more expertise than me, but hot hard start on Diesel sounds like worn injector pump head to me.

 

[Dieseltech]

Do you have a dead miss on cyl #2? That injector will bypass the cyl fuel to the return side when it fails, and others MAY be starting to do the same thing. If it starts hard when hot only, that can be a worn injection pump hydraulic head too..

 

[tomstractorsandtoys]

Sounds like the head and rotor are bad in the injection pump. Try pouring some cold water on the pump and see if that helps. Dad had a 2240 that we did that for a whole summer before we had time to get it rebuilt. Tom

 

[David G]

You want to be REAL careful dumping cold water on the pump head, as it can contract and seize.

 

[tomstractorsandtoys]

I agree that you could ruin a good pump but if his is that bad it will help him get going untill he can replace or rebuild. Tom

 

[Jim.ME]

He also mentions it spins fast when cold so I questioned his starter. Maybe he will clarify if hard to start is a cranking speed issue or if it is spinning ok but not firing.

 

[Patrick C Potter]

Thanks everyone for your replies, sorry I haven?t replied
before now we have rain coming in today and I?ve been trying
to build a cover before it gets here. I was leaning towards fuel
one person mentioned cold starts when you hit the starter it
spins fast and near immediate start after it cranks it does have
a miss I?m certain it?s the #2 cylinder fuel is getting to the
injector but not past the injector, when I idle up the motor to
start projects it tends to smooth out and when it?s ran a while
you have to be careful when you go to idle it will die.
Again thanks
Patrick

 

[Jim.ME]

When you have the hot start problem, does it spin over just as fast and easy as when cool or does it spin over much slower and seem to turn over harder?

 

[Patrick C Potter]

No when you try to start it after it's ran a awhile it sounds like a weak battery and has a hard time turning overafter it's hat
had a while to cool off it'll start right up.
Thanks
Patrick

 

[Patrick C Potter]

When it's cold it spins fast and near imediate start when hot it barely spins I put a brand commercial 950 CCA battery on it Sunday
and it still does the same thing

 

[old]

Sounds like a starter on it way to going bad. Hot it is binding up in the bearings etc. Cold things are loose so it does not bind up

 

[Tx Jim]

While attempting to start engine did you vigorously rock steering wheel from side to side as Jim.ME stated to do????

 

[Patrick C Potter]

No I?ve never done that I should be using it again within the
next day or so it?s very wet today, a curiosity question though
what does turning the steering wheel back and forth
vigorously as you say have to do with being hard to start.
Thanks
Patrick

 

[Jim.ME]

Short answer: It relieves the pressure the hydraulic pump is trying to make due to system leakage (internal or external). These are closed circuit hydraulic systems which always try to stay at a stand by pressure and don't unload until reached thus loading the starter. More of an issue when warm than cold.

Open center systems just let oil go back to the reservoir at very low pressure when the pump turns with no oil being called for by moving a valve.

 

[Patrick C Potter]

I kind of thought that but wasn?t sure but our system ain?t
closed anymore it?s a sponge LOL
Patrick

 

[old]

When hot does it spin over like it does when cold?? If slow when hot but ok when cold I'd pull the starter off and have it checked