Does not start when hot

   / Does not start when hot
  • Thread Starter
#21  
Went over it with a meter and the dynamo has two wires coming out of it - 20V against the ground each - but looks like the rectifier is shot since nothing comes out as far as I can see and measure without taking the cover off.

It looks like there is one (+) cable from the battery to the starter and the wire from the rectifier connects to battery cable at the starter. When the motor is running, I have 12.5 V on the starter connector. I suppose when the rectifier is working it the voltage higher than 12.5 will push its way to the battery, but since it is not working, all I get on the connector is the battery voltage.

Schema would be great if anybody has one.

Thanks!
 
   / Does not start when hot #23  
Take the battery and the alternator out, bring them to an auto parts store and have them tested.

But it sure sounds like your alternator or voltage regulator is shot. You should generally see 14V+ when the engine is a bit above idle.

Oh and if the battery is 5+ years old, just replace it flat out. That is getting to the age where they just start to fail.
 
   / Does not start when hot #24  
Oops... I may have missed something... Is it an alternator ???
I thought he said he had a dynamo... They would be different, dynamo always have an AC out put... KennyV
 
   / Does not start when hot #25  
Not sure. Only mention of dynamo is in that last post. How old is this Kubota? What model? I thought they were all alternators now... I know diddly about dynamos...
 
   / Does not start when hot
  • Thread Starter
#26  
It is Kubota B1750 from 80ties? I took the thing out, Autozone said they cna do nothing with it. Rigged it with an electrical motor and at 3K rpms or so it gives 25v between the wires.

As far as what it is - you tell me, it looks like the picture. From checking it out with meter, I think the rectifier is shot, but why would it give 25?
 

Attachments

  • Dynamo.jpg
    Dynamo.jpg
    66 KB · Views: 303
   / Does not start when hot
  • Thread Starter
#27  
I did some research:

Most of the older BX's (pre 2006) came std w/a Dynamo whereas later model BX's (2006 and above) come w/an alternator. Knowing which device you have will determine how much of an electrical load your BX can operate and still maintain a proper charge on the battery.
The Dynamo is easily distinguishable from the alternator. it is much smaller and has a solid body without any cooling vents. It is a form of alternator but it is less robust. It is rated to put out approx 14 - 15 amps at full governed engine speed.
Like the bigger alternator, it produces an alternating currrent (AC) which is both rectified and regulated by an external voltage regulator mounted under the dash.

this comes from here

In my country is the name dynamo reserved for a DC current generator - just a side note.
 
   / Does not start when hot
  • Thread Starter
#29  
Thanks, Kenny, you confirmed my thinking.

But the regulator is likely at fault, since there is only 12.5 (battery voltage) on the common point (starter) for the battery and regulator.
 

Tractor & Equipment Auctions

2017 DB800XL Dual Dustless Blaster Trailer with Rotair 425CFM Compressor (A48837)
2017 DB800XL Dual...
JOHN DEERE 643 - 6 ROW CORN HEAD (A50459)
JOHN DEERE 643 - 6...
16ft 3in Box Blade (A48837)
16ft 3in Box Blade...
2016 Chevrolet Impala LT Limited Sedan (A48082)
2016 Chevrolet...
HEAVY DUTY QUICK ATTACH PALLET FORKS W/ 48" FORKS (A50460)
HEAVY DUTY QUICK...
UNUSED KJ DBL PLY POLYESTER WEBBING SLING (A50460)
UNUSED KJ DBL PLY...
 
Top