BX1800 Starting Problem

   / BX1800 Starting Problem #1  

Dave A

New member
Joined
Dec 29, 2025
Messages
1
Tractor
Kubota BX1800
My 2003 BX1800 with 1,500 hours has starting issues. Although starting has been intermittent in the past, it now won’t start at all. I thought I had a problem with one of the safety switches. However, I’ve ruled that out because of the following. When I turn the key all the way to the start position, I get a click from the starter solenoid which seems to indicate all safety switches or acting properly since juice gets to the solenoid. If I place the tractor in gear so a safety switch is engaged, there is no clicking to the starter solenoid. Seems to me this would indicate either a bad solenoid or starter. I’d appreciate any thoughts.
 
   / BX1800 Starting Problem #2  
You didn't say but assuming battery is good, check for loose or corroded connections at the battery and starter. Might be good enough to tigger the solenoid but not enough to turn the starter.
 
   / BX1800 Starting Problem #3  
Time for a voltage drop test. You'll need to pull the cowling off first thing so you can get to the starter and solenoid. On my BX22 the issue was not enough voltage on the solenoid trigger wire. (Black with white stripe I believe) When the ignition switch is put into the "start" position what voltage to you get? Mine was around 10 volts which was not enough to engage the starter. I put a slave "low voltage relay" on it to engage the solenoid. If that is the issue we can give instructions on how to do that. The next test (what I would do first probably) would be to jump the starter battery terminal to the solenoid terminal (the little spade terminal the black with white stripe is connected to) which will engage the starter provided you have good voltage all the way from the battery to the starter, and the starter and solenoid are good. Report back with results if more help is needed.
 
   / BX1800 Starting Problem #4  
On my BX2200, I'd encountered dirty battery connections numerous times. I pull the cables and battery, and I get my terminal cleaner tool and brush, brush, brush till it's shiny. I blame it on the cooling system on these machines allowing all the chaff and dirt to get all over the battery and it's connections.

I do recommend doing a load test (not just a voltage test) on the battery using a battery test tool. A good battery load tester is a battery pile load tester, as it uses resistive heating element. Or bring it to any major auto parts counter and they can do it for free.
 
   / BX1800 Starting Problem #6  
Cut to the chase. This exact issue has been thoroughly discussed and solved many times here on TBN over the last several years. I'm too lazy to look up the best version for you so here is mine: All the suggestions about cleaning terminals, sanding the surface under ground cable bolts, load testing the battery, etc. are all good. Go ahead and do that but it is not your long term solution. Here is: 1) No matter how good your battery tests or seems to be, put a battery charger on it and see if the engine will start. Probably will. The reason is you get voltage drops at all of the many safety interlocks between the battery and the solenoid primary and by the time it gets to the solenoid it is often not quite enough to engage the starting current. The charger puts out roughly 13.8v (not 12v) and that difference is usually enough to overcome the various drops. If that works it proves your problem. 2) Many if not most manufacturers of small diesels like yours pinch pennies and do not provide a pre-solenoid relay that is happy with much less than 12v and will lay the full 12v on your solenoid when you turn the key. By no coincidence John Deere sells a kit for installing that pre-solenoid relay. So do many Kubota dealers calling it a "hard start kit" which is a poor description but so be it. You can get one of those kits and almost certainly fix your problem (or make your own kit if you like buying parts and making things.) Let us know the outcome.
 
   / BX1800 Starting Problem #7  
I will add to check the fuses; not just the ones in where the battery is, but also those off to the side...I cannot remember if it's left or right side...
 
   / BX1800 Starting Problem #8  
Cut to the chase. This exact issue has been thoroughly discussed and solved many times here on TBN over the last several years. I'm too lazy to look up the best version for you so here is mine: All the suggestions about cleaning terminals, sanding the surface under ground cable bolts, load testing the battery, etc. are all good. Go ahead and do that but it is not your long term solution. Here is: 1) No matter how good your battery tests or seems to be, put a battery charger on it and see if the engine will start. Probably will. The reason is you get voltage drops at all of the many safety interlocks between the battery and the solenoid primary and by the time it gets to the solenoid it is often not quite enough to engage the starting current. The charger puts out roughly 13.8v (not 12v) and that difference is usually enough to overcome the various drops. If that works it proves your problem. 2) Many if not most manufacturers of small diesels like yours pinch pennies and do not provide a pre-solenoid relay that is happy with much less than 12v and will lay the full 12v on your solenoid when you turn the key. By no coincidence John Deere sells a kit for installing that pre-solenoid relay. So do many Kubota dealers calling it a "hard start kit" which is a poor description but so be it. You can get one of those kits and almost certainly fix your problem (or make your own kit if you like buying parts and making things.) Let us know the outcome.
X1000!!!!!
 

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