JD x758 hard starting

[Shawn Strader]

I have 2 x758 mowers that I maintain. One starts no problem regardless of the time or year or time of day. The other has always been a little slower to start but now has gotten to the point where it requires a lot of cranking.

I know that the glow plugs are not working, neither is the pto switch operating properly. Started when the original dash panel had a prong corrode in two and mower quit completely. Repaired the prong, reinstalled, mower ran again but deck was non functional and glow plugs the same. Direct wired the deck switch but don't want to have to put a toggle on the glow plugs. Would like to be able to put all components back to original.

A new dash panel didn't cure any issues (tried 2 new ones) , nor did new relays for the glow plugs, etc. When I test the "power" to the relays, I'm getting nothing through the dash panel. All fuses are good.

I've stared at the schematic until my eyes crossed.
I'm missing a sequence of events that occur on startup and was hoping someone could steer me in the right direction for repair.
I have a TM ordered for the 758 but would like to get it out of the shop sooner since Deere is so slow with the manuals.
TIA

 

[buickanddeere]

duplicate post

 

[beenthere]

Shawn
How soon do you think you will get the service tech manual?
What schematic are you staring at if you don't already have the manual?

:welcome: to TBN

 

[Richard001]

You could just buy an automotive starter relay and a momentary switch and hook that up to power the glow plugs.

Richard

 

[Shawn Strader]

the oil is bought bulk and recommended by Deere.
Levels are correct.
PVC system is functionally correct.
Machine is used commercially by men who didn't buy it, so "putt" is not in the vocabulary.
T stat is also good.
Thanks

 

[Shawn Strader]

John Deere is painfully slow on the manuals.
My guess is another week. And that's the digital copy!!

I have a good working relationship with the local dealer and they will get me what I need information wise. The service department printed the schematic for me.

 

[Shawn Strader]

Yes, but this is used by employees, and I prefer to have things as intended to avoid the temptation to break things further ��
I did bypass the deck switch safety and within a few hours it was puking antifreeze because the operator was not watching the temp gauge. A quick fix here is long term troubles every time.

 

[Shawn Strader]

Today I will be putting the two x758s side by side and going through them.

 

[Richard001]

Yes, but this is used by employees, and I prefer to have things as intended to avoid the temptation to break things further ��
I did bypass the deck switch safety and within a few hours it was puking antifreeze because the operator was not watching the temp gauge. A quick fix here is long term troubles every time.

Wow, I didn't know that JD made equipment that would only work as long as you kept an eye on the water temp gauge.

Perhaps there is an issue with the cooling system. Radiator fins full of crap? Water pump fins worn away? I don't know, but this doesn't sound right to me.

Richard

 

[Shawn Strader]

These newer machines all have a safety built into them that stops the pto when the temp gets too hot. By bypassing the pto, it allowed the deck (pto) to keep turning when it should have shut down and prevented the overheating.
Usually all the operators have to do is shut them down long enough to clean the radiator screen and keep rolling.