John Deere 8500 Cancel The title field is required!

1. Kyle Fick

   

   4 posts
   
   7/25/2017 4:07 PM

   Fellow individuals that are into troubleshooting and repairs, I have a question to you all.
   
   This morning, one of our 2 8500 JD's simply wouldn't start. I serviced them and used them both yesterday and all was good. The operators then proceeded to put about 4 additional hours on in the afternoon, and all was great. They washed and parked as normal. Then this morning happened to the one. When we turn the key, the cluster gauge get's drawn down instantly, and you can here the relays under the seat buzzing abnormally loud. The engine will not crank over.
   
   I went to start trouble shooting, and here's what I've come up with. I switched a few components between 1 and 2 I thought might be a quick fix for diagnostics (battery, key switch, a couple other small things), and no results. I then started tracing wires and checking for voltage as I should to make sure we had good power to all. We eliminated components one at a time coming from the battery itself and I think I am now stumped into an idea.
   
   I crossed the starter, it would go if need be. I have proper voltage to all the supplies in the harnesses that go to the relays under the seat. Fuses are good, diode is also (however I didn't suspect it). I had same voltage to the power in on the key switch. When I put a load onto the system, voltage out was significantly lower coming back out of the key, the relays buzzed and rattled ( I could physically feel them vibrate), and nothing kicks on. Even the lights wont' flicker on at all. I really thought it'd be the key switch, but when I stole the like machines and tried it out, nothing, same results of what seems like a bad short and a power loss. I tried robbing the relays and going from the lights to the start, the lights to the fuel system, the lights to the prestart relay, and so on and on. No luck whatsoever.
   
   I've spoken to a couple other folks, and they seem stumped. One said to check the fuel shutoff solenoid, one feels its in our relays, and another told me now on on my own.
   
   I ordered the relays to change out, however I'm skeptical of them being the culprit. I'm struggling to locate the fuel shut off solenoid, but I know the pump does run, and there's power there obviously, but I felt it might be a little weak on my volt meter.
   
   I'm really taken aback that even the lights won't come on. I thought of a couple more small things, but I'm not holding my breath. I'm pretty much at the end of my abilities I feel, and I'm good admitting to that. But if anyone can offer me any hints, insights or advice, I'd never turn it down.
   
   Thank you very much,
   Sincerely,

   
   
   
   
2. Frank McQuiggan

   

   2 posts
   
   7/26/2017 4:07 AM

   Check all your ground wires, sounds to me like you have a ground problem. Voltage looks good without load but under load voltage drops drastically I would defiantly look at the main grounds.

   
   
   
   
3. Kyle Fick

   

   4 posts
   
   7/26/2017 6:07 AM

   Frank,
   
   thanks for the response. We did remove the grounds, used sand cloth to clean up ends and contact points to the frame, and that didn't help. Unless I missed a spot. I had where the batter negative cable goes directly to the frame, and then where the engine block and the starter side are bolted to the right hand side.
   
   I too had the hunch it was a grounding issue.

   
   
   
   
4. Michael Kriz

   

   0 posts
   
   7/26/2017 7:07 AM

   Kyle: How old are your machines?
   
   Check your battery cables, both positive and negative from the battery posts to next connection. Cables occasionally develop hard spots (become very stiff at that point) Normal voltage will show on a meter but once a load is applied the machine exhibits your symptoms

   
   
   
   
5. Keith Lamb

   

   3 posts
   
   7/26/2017 11:07 AM

   https://docs.google.com/file/d/0Bxb5iFHmLry0UjM0ZGhhanhnS3c/edit
   
   Lightweight Fairway Mower 7500, 7700, 8500, 8800 Technical Manual

   
   
   
   
6. Kyle Fick

   

   4 posts
   
   7/27/2017 2:07 PM

   The problem ended up being a bad spot on our positive battery cable going to the starter from the post. Thank you to all the people who took the time to reply. The expertise and experience shared on this forum has helped numerous people for sure.
   
   As a side note, I'd have never thought that the positive cable being bad would allow me to still get normal voltage readings before the load. I'd have thought we'd have experience a power loss prior. Great advice again.

   
   
   
   
7. Kyle Fick

   

   4 posts
   
   11/26/2018 2:11 PM

   Good afternoon all. We have some 8500's and I don't care for how the edges of the cutting units are adept at grabbing the sod around some small features like heads, drain boxes, and any other subtle depressions. I realize one answer would be to work on the ground to flatten the low heads, deep valve and drain boxes, and so on, but I am looking for a quicker remedy that requires less labor. We have way to many of these to do it in a spring or fall. More of a work in progress following construction and so on (a lot of settlement occurred due to various factors).
   
   A little more info: QA5 cutting units but they came factory with a 2" front roller. The roller bracket is what seems to be snagging when an end of the cutting unit falls into a said depression. It is pretty blunt. I was wondering if 3" rollers would make a difference (2400 to do all 5 cutting units twice, 1200 per machine, is kind of an ouch, but able to do it), or is there a skid shoe that could work out here? I have seen them on other units, and a one publication advertises the use for 7500's only, but what are you all thinking?
   
   
   Thanks for any advice or insights.

   
   
   
   
8. Kyle Fick

   

   4 posts
   
   11/26/2018 2:11 PM

   Good afternoon all. We have some 8500's and I don't care for how the edges of the cutting units are adept at grabbing the sod around some small features like heads, drain boxes, and any other subtle depressions. I realize one answer would be to work on the ground to flatten the low heads, deep valve and drain boxes, and so on, but I am looking for a quicker remedy that requires less labor. We have way to many of these to do it in a spring or fall. More of a work in progress following construction and so on (a lot of settlement occurred due to various factors).
   
   A little more info: QA5 cutting units but they came factory with a 2" front roller. The roller bracket is what seems to be snagging when an end of the cutting unit falls into a said depression. It is pretty blunt. I was wondering if 3" rollers would make a difference (2400 to do all 5 cutting units twice, 1200 per machine, is kind of an ouch, but able to do it), or is there a skid shoe that could work out here? I have seen them on other units, and a one publication advertises the use for 7500's only, but what are you all thinking?
   
   
   Thanks for any advice or insights.

   
   
   
   
9. Anthony Lewis

   

   1 posts
   
   11/26/2018 6:11 PM

   I would ask your sales rep to demo either a 8500 with 3 inch rollers or let you try the rollers before you buy them on one unit. There is a slope leveling kit worth asking about as well. I believe that is different than the skid shoes and designed more for stability. Good luck

   
   
   
   
10. Bob Pruneau

    

    5 posts
    
    11/30/2018 3:11 PM

    I would fix the cause . Get the worst ones first . Any mower will grab unlevel heads and boxes doesn't matter what color . Hmm 3" roller? HOC is measured off rollers so I don't think it would help . Also hitting the feed end of reel ( left side sitting on machine ) will surely bend the reel lands or bedknife. For the price of rollers it may be cheaper to get a few guys leveling stuff up for a few weeks .

    
    
    
    
11. Kyle Fick

    

    4 posts
    
    12/1/2018 10:12 AM

    I've been looking at this a little further and am going to try turning the bracket outwards away from the reel itself. This will put the clearance I'm after in the right place. I don't think I have to worry about the span between the front roller and bedknife and the possible "scalp" that could occur. At .650, I'd think it'd be so negligible no one will ever notice.
    
    Agreed, the leveling of imperfections is ideal, and an ongoing task. I am just looking to balance the issue while progress is being made. I'll be completing my winter service on these units shortly, and will attempt to post a picture when I get the machines in the mechanics bay. Might bring some more clarity to the question at hand.

    
    
    
    
12. Bob Pruneau

    

    5 posts
    
    12/1/2018 3:12 PM

    At that HOC it shouldn't be a problem. Good idea