Jd 300b hard to start when hot

[Mallard1]

Have a 70痴 model John Deere 300b backhoe that on the first crank of the day will bust right off easily. However after warmed up the starter has a tough time spinning the motor. The battery is a few years old but even with jumper cables it wont crank. The only way I can get it to crank is to have the stabilizer lever pushed to lower while also using the key. I guess this is taking the pressure off the hydraulic pump. I also have the boom on the ground and the front end loader in float. With the clutch fully depressed.

Is this a bad accumulator? Bad injector pump?

Once cranked it runs fine for a machine with 4100 hours. Thanks for the help.

 

[Zebrafive]

What you are doing does take off some of the hydraulic pump load off. Another trick is turn the steering wheel side to side.

I am not sure where the ground cable connects on your 300b. but on my JD 2030, it connected to the sheet metal of the battery box. I ran a longer cable to the engine block (one of the bolts for the fuel filter mount).

What really helped was a gear reduction starter.

 

[Tx Jim]

If none of above helps you might consider installing this electric operated hyd destroking valve. RE32529 VALVE, SOLENOID DESTROKE ADD 241.57 USD

 

[Mallard1]

If none of above helps you might consider installing this electric operated hyd destroking valve. RE32529 VALVE, SOLENOID DESTROKE ADD 241.57 USD

Thank you for this. I looked at the diagram and it looks like it just needs one side grounded and the other to the start wire from the key switch. Which port on the hydraulic pump does it screw into? Thank you for your help

 

[Tx Jim]

What is your tractor's serial #? Does hyd pump have a serial # plate?

 

[Mallard1]

What is your tractor's serial #? Does hyd pump have a serial # plate?

Tractor serial number is 300BD 281699T
Back hoe serial number is 9250 A 038713T

I saw the pump serial number plate this weekend, I will grab a picture of it Friday. Thank you for your help.

 

[number two]

Perhaps you have a heat-soaked starter?

Good Luck!

 

[Jerry/MT]

Failure to start when hot could very well be a worn injector pump.

 

[Mallard1]

Well I went down Friday with the intention of taking a picture of the pump serial number but I forgot. I moved some trail cameras around. Knocked out the last 3 pins and got them to take grease, now everything will take grease on the backhoe. When I pulled up back at home I remembered why I went down there. I値l try to do a better job remembering this weekend

 

[Mallard1]

I made it down today here are the pictures

 

[Mallard1]

Is the red arrow where the solenoid screws in?

 

[Tx Jim]

Your tractors hyd pump appears to be the non-serialized type which would require a more expensive electric controlled valve(RE40463 @ $871.66). From viewing your photo it appears that your tractor's hyd pump has a manually operated destroking screw(see photo below)

 

[Mallard1]

Your tractors hyd pump appears to be the non-serialized type which would require a more expensive electric controlled valve(RE40463 @ $871.66). From viewing your photo it appears that your tractor's hyd pump has a manually operated destroking screw(see photo below)

Thank you for your help. I didn't mind spending the $250 for the solenoid but for the $850 and as little as the backhoe is used I think i'll give the screw a try. I think i read somewhere the process is to screw down until resistance is felt then a couple turns to get it started. after started back it back out. is this correct?

 

[Tx Jim]

Thank you for your help. I didn't mind spending the $250 for the solenoid but for the $850 and as little as the backhoe is used I think i'll give the screw a try. I think i read somewhere the process is to screw down until resistance is felt then a couple turns to get it started. after started back it back out. is this correct?

Yes that's correct.

 

[Mallard1]

Yes that's correct.

Thanks Jim, I believe this fixed my issue, I went down there Friday and it was slow to start. I used a 1/2 wrench to tighten it down. After that it spun over fast and cranked right up. Once I backed the bolt back out the hydraulics came back. Now I just need to find a good spot to keep a 1/2 wrench stored on the backhoe.

 

[Tx Jim]

You're welcome

 

[finn1]

Hot start problems on a Diesel engine are usually caused by a worn out injection pump. The clearance between the plunger and barrel increases as the pump wears, and the viscosity of diesel fuel drop as fuel temperature increases. Net result is that the pump leaks internally such that there is insufficient fuel delivery hot to start the engine.

By reducing hydraulic pump pressure, you are reducing parasitic loads at cranking speed. The result is higher cranking speed, which masks the high leakage from the worn pump.

A bandaid solution, but it doesn’t fix the root cause of hard hot starting....a worn out injection pump.

 

[Tx Jim]

finn1
Many JD tractors built from '61-'92 with the closed center hyd system are difficult to start due to the hyd system not just worn inj pump. I'll bet you wouldn't be a happy camper if you had a JD tractor with a freshly rebuilt inj pump was still hard to start after it had been operated long enough to get hyd's to operating temp.

PS: After serving as a JD dealer service manager for 13 yrs I'm very familiar with the symptoms of IP that has a worn head & rotor just as I am with hyd problems on the previous mentioned JD tractors

 

[true temper]

Finn you don’t know what you are talking about, new injector pump is not the answer.
Listen to Tx Jim, he knows