JCB 530 B Alarm sounding

[mtown]

I have a 1980's JCB 530 forklift. I have owned it since new and an alarm will sound if the key is on but motor not running. It also sounds for a brief time as the motor warms up.
Just the past two days it has stayed on for minutes, then when started a little later only sounds a few seconds.
While it sounds the fuel gauge shows empty and as soon as it stops the fuel reads correctly. I checked oil, and am sure it is not an overheat warning. This machine sits unused for months at a time, but has always started and run fine.
Any thought are appreciated.

 

[jcb jeff]

Do you have lights on the dash panel you could check the charging of the alternator or the belt tension as this would be under load when first starting so as to recharge battery from starting as like you say it sits unused for a while the alternator will need to charge the battery back up so check fan belt is tight and charging with a meter looking for about 13.7 - volts there abouts.

 

[mtown]

There is a red light on the dash that is red and has a lightning bolt symbol. It is lit when the key is on but not when the motor is running [similar to a car]. I have been using the lift recently and tested the battery after charging over night. It was at 13 volts. I disconnected it from the cables and it was dead the next morning in mild weather. So the battery was bad.

Replaced yesterday and all was fine, started and ran with no alarm. It was running about 10 minutes while I moved it to it's parking spot. Just as I was about to turn it off the alarm sounded and stayed on, and the fuel gauge went to empty as it always does.
Just to be sure it had nothing to do with overheat I opened the radiator cap. It was full and a little got on my hand. It was not even hot.

Thanks for your reply.

 

[jcb jeff]

Need to put a volt meter on when machine is running so as to determine if the alternator is actually charging or not also check all your earth cables for the battery to chassis and chassis to engine as this is all rubber mounted.
Alternators can go to ground and discharge the battery to nothing so it needs checking when the buzzer sounded before you stopped it did any lights come on on the dash?
It sounds if you have a drain over night so something is drawing voltage could be radio if you got one or something like that.