KUBOTA DIESEL RX 125-2X-GE will not start

Frank A.

New member

Equipment
KUBOTA DIESEL RK125 2X-GE
May 22, 2025
3
0
1
Vietnam
Engine used on my standby generator has served me well for more than 25 years. Then electrical power became more and more dependable, and the usage fell off dramatically. Trying to start it now (hand Crank), no sign of fire. Fuel is full but it has been there more than six months since the last time we ran it. Where should we begin to check out/discover the problem? Never had a bit of trouble before. It is inside and the temperature is in the 80s. Thanks men!
 

Russell King

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Lifetime Member

Equipment
L185F, Modern Ag Competitor 4’ shredder, Rhino tiller, rear dirt scoop
Jun 17, 2012
6,124
1,873
113
Austin, Texas
I would start by looking at fuel supply and see if fuel is getting to the injection pump, filter, out of the tank, up to the injectors.

I would assume that a biological growth has started in the fuel and is clogging up the system somewhere.

Report back what you find, add some anti biological treatment to the fuel, replace the filters…

Good luck!
 
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Frank A.

New member

Equipment
KUBOTA DIESEL RK125 2X-GE
May 22, 2025
3
0
1
Vietnam
I would start by looking at fuel supply and see if fuel is getting to the injection pump, filter, out of the tank, up to the injectors.

I would assume that a biological growth has started in the fuel and is clogging up the system somewhere.

Report back what you find, add some anti biological treatment to the fuel, replace the filters…

Good luck!
Thank you Russell, I'm an old, retired aircraft engineer type fellow with far more experience around a turbine engine than these little fellers.
I'll start by removing the fuel tank and cleaning it. Then I'll try to source a replacement filter and that biological agent. Will get back to you on that. Thanks again.
 

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Russell King

Well-known member
Lifetime Member

Equipment
L185F, Modern Ag Competitor 4’ shredder, Rhino tiller, rear dirt scoop
Jun 17, 2012
6,124
1,873
113
Austin, Texas
Since that is a steel tank you might have rust forming at the inside bottom of the tank.

First step I would suggest is to see if fuel is freely flowing out of the tank by removing the bottom of the hose to the separator filter. That would be conclusive if it is a fuel flow problem.
 
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