Weird Mower Problem--Kubota F2400

[333jeffery]

I have an old Kubota F2400 diesel mower that I bought used a few years back. It has a weird problem that I have not been able to solve: it won't start unless I put a booster on the battery. I've replaced the battery, starter, alternator, key switch, even put new battery cables on. It acts like it is not getting enough current to spin the starter, but once I put a booster on it cranks right up. Any help would be appreciated. Thanks.

 

[millerbl00]

Bad ground somewhere.

 

[jhellwig]

It is not nessecaraly a ground problem.

An easy way to check is to make a jumper wire with a switch and jump from the battery positive directly to the soilenoid engagement terminal. Most likley it is a non bendix style starter. If the starting circuit is getting high resistance it can let the soilenoid go in far enough to engauge the gear but not pull on the contacts to run the starter. This is commonly accompanied with a click/clunking sound but no spinning of the starter. There can be a numerous amount of bad connections or bad saftey switches that can cause this. The reason it will start when you put a charger on it is that it brings up the voltage high enough to overcome this.

If that does not fin the problem and/or you are using a booster pack instead of a charger to start it it may be a battery problem.

Another good thin to check would be to make sure the battery terminals are clean and the cables are in good shape and have good connection on both ends.

I had a similar problem with my deere 318. If I put a charger on it it would sometimes work. I replaced every switch and each on make it work better for a little while but finaly is got bad enough that you had to jump the soilenoid or spin the flywheele to get the starter to turn. Deere makes a relay kit that simply put 12 volts from the battery cable to the soilenoid. The relay was engaged by the start circuit. The system just got to the poin where it couldn't pull in the starter but could pull in the relay. It solved the problem and I haven't had a issue since.

 

[gman2304]

Like jhellwig said there is a 'starter assist relay kit' that is available for numerous riding mowers. I don't know if it will work on your diesel Kubota but it worked on a friends cub with a Kohler twin. I would check with a Kubota dealer and see if one might work on your diesel.

 

[333jeffery]

It does make a clicking noise, but I have replaced the battery and cables with no effect.

 

[TFB1]

Are you sure the CCA of battery is high enough for this application??? Diesel is going to have probably at least a 15:1 compression ratio, are hard to spin...