Another No starter rotation thread

GeoHorn

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M4700DT, LA1002FEL, Ferguson5-8B Compactor-Roller, 10KDumpTrailer, RTV-X900
May 18, 2018
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Texas
My M4700 is a pretty simple tractor...or so I thought... Only one safety switch activated by the range-lever (the forward-Reverse-Low-High selection lever) on this DT (manual transmission.). The neutral start safety switch is kind of troublesome to get to... and that was my suspicion because occasionally turning the key would not result in engine rotation despite other things lighting-up (such as a high battery-discharge from the GlowPlugs which apparently heat up anytime the key is turned to Start.)
But if I wiggled that Range lever a couple times it would usually turn over quickly and start.
However this afternoon.... no joy. Wiggle that lever to death and no rotation.

Grab a VOM and 12 volts available at the big starter-terminal (direct connection from Positive Battery Post, of course.)... but no rotation. Pulling the little spade connector off the starter-solenoid I only measure 10-volts when the key is turned to the start position.

I struggled beneath the tractor and reached over the rear axle and disconnected the neutral start switch associated with the Range Lever and by-passed the switch. No joy. :devilish:

Grabbing my good ol’ Snap-On push-button starter-by-pass switch, I hook one alligator clip to the big starter terminal and the other alligator clip to the spade terminal on the starter-mounted solenoid...and she starts right up!
Soo... apparently 10 Volts ain’t enough (perhaps low current?) but direct-connection to battery voltage will rotate the starter.

I believe the last time this happened I suspected another heavy-duty relay (the pic on the far right below of the black plastic relay) inside the instrument panel that Kubota wants $110 for (and cross-reference aftermarket part is the same)... I had disassembled it and used my wifes nail-file to clean the points and the starter worked again. Perhaps this is the problem this time also... but somehow I was reluctant to believe it Previously and this time I wasn’t convinced either.

I have a heavy-duty metal-can relay (The pic on the far left below... a “grounded” relay...meaning just like the black pastic one, it requires power to it’s little terminal to close the relay main contacts... (as opposed to the typical “powered“ automotive relay that is not grounded and the little terminal is looking for a ground to close the main contacts).... It is a $20 part and I plan to replace the cheap plastic $110 Kubota part with this large metal $20 one and I’ll report back.
 

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Dave_eng

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M7040, Nuffield 465
Oct 6, 2012
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My M4700 is a pretty simple tractor...or so I thought... Only one safety switch activated by the range-lever (the forward-Reverse-Low-High selection lever) on this DT (manual transmission.). The neutral start safety switch is kind of troublesome to get to... and that was my suspicion because occasionally turning the key would not result in engine rotation despite other things lighting-up (such as a high battery-discharge from the GlowPlugs which apparently heat up anytime the key is turned to Start.)
But if I wiggled that Range lever a couple times it would usually turn over quickly and start.
However this afternoon.... no joy. Wiggle that lever to death and no rotation.

Grab a VOM and 12 volts available at the big starter-terminal (direct connection from Positive Battery Post, of course.)... but no rotation. Pulling the little spade connector off the starter-solenoid I only measure 10-volts when the key is turned to the start position.

I struggled beneath the tractor and reached over the rear axle and disconnected the neutral start switch associated with the Range Lever and by-passed the switch. No joy. :devilish:

Grabbing my good ol’ Snap-On push-button starter-by-pass switch, I hook one alligator clip to the big starter terminal and the other alligator clip to the spade terminal on the starter-mounted solenoid...and she starts right up!
Soo... apparently 10 Volts ain’t enough (perhaps low current?) but direct-connection to battery voltage will rotate the starter.

I believe the last time this happened I suspected another heavy-duty relay (the pic on the far right below of the black plastic relay) inside the instrument panel that Kubota wants $110 for (and cross-reference aftermarket part is the same)... I had disassembled it and used my wifes nail-file to clean the points and the starter worked again. Perhaps this is the problem this time also... but somehow I was reluctant to believe it Previously and this time I wasn’t convinced either.

I have a heavy-duty metal-can relay (The pic on the far left below... a grounded relay...meaning just like the black pastic one, it requires power to it’s little terminal to close the relay main contacts... as opposed to the typical automotive relay that is not grounded and the little terminal is looking for a ground to close the main contacts).... It is a $20 part and I plan to replace the cheap plastic $70 Kubota part with this large metal $15 one and I’ll report back.
Great diagnostic work.

I too have resorted to the "Ford " style starter solenoid/relay.

I suggest you check the current draw necessary to close the metal can relay. I found it to be significantly higher than the smaller relays and this added current draw accelerated the breaking down of the safety switches completely. It worked in the beginning but soon failed.

I ended up using a small relay to fire the metal can style.

My experience is limited to one or two situations so do your own checking.

Dave
 
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Chesapeake

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B6100
Apr 1, 2021
27
8
3
Washington
Can’t really be sure on the pin out or the connection of the relay, but suspect this one is similar/same.

The part used for Kubota and JD looks like nippondenso 056700-6690.

Hard to find specs but looks like a 12v, 20amp relay.
You should be able to find a suitable version from another industry that has higher volume and lower margins.
You may have to re-pin your connector if they’ve swapped coil and contact pin out on the alternative models.

 
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GeoHorn

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M4700DT, LA1002FEL, Ferguson5-8B Compactor-Roller, 10KDumpTrailer, RTV-X900
May 18, 2018
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Texas
Chesapeake, you and Dave have provoked me to look further into this and I’m indebted to you guys for raising my suspicions further:
This tractor was purchased used but very low hours (~400) ... and I found some sneakiness by the former owner who had removed warning lamps/sockets from the panel to disguise mouse-damage to wiring:
One lamp warned of low-fuel/no-charge and had been removed.... which hid the fact the alternator was low-output. I replaced the alternator but also installed an ammeter ... and only later, having obtained an Owner’s Manual and reading thru it, discovered the missing lamp function... clearly it was a deliberate action to hide a low-output for any buyer (me...and I did not perform due-diligence when “inspecting” by bringing-along a VOM.... I mean... It started and no warning lights, right? Doh!)
I ordered the lamp-holder from the local Kubota dealer and deliberately ran the fuel low to assure the warning would light-up at 2-gals remaining. (Another educational experience gained by reading the Owner’s Manual.)
(The temp-gauge also only displayed “cold” and until I’d owned this thing awhile and never saw any indications....became suspicious... and sure-enough, mice had chewed thru the wiring under the hood. Simple wire-repair/splice after Messicks was kind enough to email a wiring schematic to me.

SOOooo.... you guys have provoked me to look at the exploded online Messicks Parts diagrams...and to my surprise (thought I’d already figured this tractor out after three years ownership and experiencing reliable operations) ... I see the Messicks online parts diagram has small “camera” icons I could “click” on and get a Zoom—In photo of the actual part. (Chesapeake, now I see how you might have realized aftermarket parts might supplant OEM.)

Further, the exploded diagram shows more safety-start switches than I thought existed! :oops:
(Discussions previously here at OTT had agreed there was only ONE safety switch on the Range Lever...none on the seat, etc.... But that is incorrect according to THIS exploded Messicks diagram....
There appears to have ORIGINALLY been a Range-Lever switch (item 90) AND a CLUTCH switch (Item 50). This “clutch switch is completely missing so the previous owner must have removed it as well.
(I’ve also discovered the relay I’d previously filed the contacts on was not the starter relay...it was the Glow-Plug relay... so the presumed success I’d enjoyed a couple months ago was a fluke.... probably that last “wiggle” of the range-lever disguised things.)

In this particular episode of trouble-shooting I’ve already by-passed the Range-Lever switch and will likely leave it this way. (After-all...in previous start-attempts it had displayed erratic behavior and required me to “wiggle” the lever To get a start.... so having by-passed it this time... that’s THAT!)

Summary: Surprise Surprise Surprise Sergeant Carter! A used tractor might have been tinkered with by it’s previous owner and just because it’s low-time and looks good cosmetically.... doesn’t mean it is “as designed and fully-operational” ... if a sneaky previous owner has done his thing. :cool:

Sooo... Thanks Guys! It’s now 0530 (AM) and I’m going out to the shop/hangar/barn/shed (whatever you call yours) and openin’ ‘er back up to look closer and compare to the Messicks Parts Diagram.

I’ll follow thru later...

0E3F532A-411A-4D1A-BC2D-CAE431593BB0.png
 
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Motion

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Kubota MX5100HST/FEL
Aug 17, 2020
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Mandeville Louisiana
Follow the wiring diagram to see where you're losing voltage, it could be a loose/corroded wire, connection, fuse, etc.
 

GeoHorn

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M4700DT, LA1002FEL, Ferguson5-8B Compactor-Roller, 10KDumpTrailer, RTV-X900
May 18, 2018
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I LOVE IT ...when things happen like this! :love:

I opened up the instrument panel/cluster this afternoon to further investigate and found the starter relay would “click” but had reduced output of only 10 volts.
It was obvious that relay had two female spades (18 ga wires) that were activated by the key-switch when turned to “start” and that two heavier gauge wires (14 ga) were then connected inside the relay to take 12V to the starter solenoid.

Following the consensus in this thread I removed the starter relay in order to break it open and look inside...when I RECALLED that last year I had purchased a box of common automotive 40A relays on Amazon. (5-pack including pigtails/plugs for $13, free shipping) https://www.amazon.com/gp/product/B017VDI0GY/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1

I simply crimped onto the pigtails some male spades, plugged them into the Kubota female socket, plugged the pigtail-plug onto one of the relays, mounted the relay (which already had the mounting bracket with the proper hole for the original Kubota machine-bolt) and tested it by cranking with the key dozens of times ... WORKS PERFECTLY!

The color-codes of the pigtails changed but here’s the description: Kubota Red/Hot to Pigtail Blue (relay pin #30), Kubota Black w/White-stripe (which goes to the starter solenoid terminal) to Pigtail Yellow (pin 87), Kubota small, black from key-switch (two 18 ga wires) to Pigtail whiite and Pigtail black (pins 85 & 86).
Pins 85/86 are the sense-wires from the key-switch, and Pins 30 and 87 are the 12V power and start-solenoid wires respectively.) The red-pigtail lead is not used (Pin 87a is normally-closed/connected to pin 30 when relay is relaxed/not-activated. Pin 87 becomes connected to pin 30 when relay is activated. These are very common in automobiles to control air conditioning, horns, fuel pumps, etc etc.)

Sooo.. anyone else who is crazy like myself and buys things just to “have around” .... (but has a quicker memory than me and won’t forget you‘ve got them).... order the 5-pack of relays and Be Prepared (Boy Scout Motto) for when your Kubota relays die on you.

Instead of $110 plus freight... I paid 1/5th of $13 to fix this problem and have 4-more relays sitting on the shelf! (Sorry, Messicks... but Thanks for the Parts Diagrams!)

Hope this helps others.
PS: Turns out my M4700DT must have the “New Type” switch-panel (shown by another page in the Parts Diagrams), as it does not have/never had a clutch safety switch.
 

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woodsy

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95 Kubota L3300DT W/FEL 51 John Deere M 2cyl , skiddah. 89 Arctic Cat Panther
Apr 20, 2021
27
6
3
Northeast
Thanks for the detailed write up GeoHorn. Was looking at the same thing today
behind the dash so this may help me get my rig starting right again.
I get three panel lights to come on and they dim slightly when I turn the key to start but no start, just quiet.
 

GeoHorn

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M4700DT, LA1002FEL, Ferguson5-8B Compactor-Roller, 10KDumpTrailer, RTV-X900
May 18, 2018
2,326
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Texas
If anyone is reluctant to buy the $13 Five-pack of relays from Amazon... the identical (single) relay is available from CarQuest (and others) for only $5 more ... which does not include the pigtails and plug you’ll need to complete the repair ... in which case you’ll also face altering your original Kubota wiring harness with some sort of splicing operation.
 

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GeoHorn

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M4700DT, LA1002FEL, Ferguson5-8B Compactor-Roller, 10KDumpTrailer, RTV-X900
May 18, 2018
2,326
598
113
Texas
Thanks for the detailed write up GeoHorn. Was looking at the same thing today
behind the dash so this may help me get my rig starting right again.
I get three panel lights to come on and they dim slightly when I turn the key to start but no start, just quiet.
My M4700 (in which I had previously installed an ammeter) displays a large 30A DIScharge when the key was turned to ”start” despite the starter not being engaged. I discovered (confirmed by others here on OTT) that during ordinary starts, my tractor model also activates the GlowPlugs each time. (Separate/Larger relay is involved in that circuit.)

If that also occurs with your tractor, the dim lights may be due to the GlowPlugs drawing down.
 

woodsy

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95 Kubota L3300DT W/FEL 51 John Deere M 2cyl , skiddah. 89 Arctic Cat Panther
Apr 20, 2021
27
6
3
Northeast
That makes sense on the dimming .
I've only owned the L3300 for a couple weeks which has 1100 hrs.
Looks decent, in need of some TLC though.
Its quirky electrically though. Thought I was good after moving the battery ground
to the frame , everything worked great for a few days.
I think testing the voltage like you did at the starters black wire will be next.
Process of elimination, think I'm getting close.
Thanks for the input.