Kubota GR2120 losing power when hot

[5030]

Thanks guys really appreciate the input. Overheating sounds possible, it does always happen after running for some time. The fan is definitely spinning and I've seen no sign of the coolant boiling, so there's that. I did consider the "fuel tank vacuum" scenario previously and loosened the filler cap but that didn't seem to help.

I have an infrared gun-type thermometer, I wonder whether I could use that to tell whether it's overheating? I'll check the belt as that sounds an easy place to start.

All I have to add is... Clean the radiator from the fan side out with a Radiator Genie or low pressure compressed air, but if you use the Genie, first soak down the rad with dishwash detergent (I use Dawn) and let it soak in and then clean it (water or Genie)

You keep overheating it, you'll blow the head gasket. Kubota is noted for weak head gaskets,

 

[dstig1]

If you have eliminated overheating, like it sounds, then you need to get into fuel. If the filters are clear, then the tank is your likely problem... Probably time to pull it. It seems like most tractors and mowers start by grabbing a fuel tank and then building everything around them, so they are usually a total PITA to get at.

One last thought - is there a sensor that kills the engine on overheating? I know my Deere mower will kill the PTO if the temp climbs high enough, and it might even kill the motor if it goes farther, but not sure on that. I've had it kill the PTO a time or two when it was very dusty and I got slack about checking screens while mowing. Easily fixed by stopping and blowing it all out. >>>But my point here is that if you are not actually overheating, perhaps the sensor (if you have one) is giving bad readings and killing the motor.

 

[MHarryE]

I see someone said it but remember 2 filters, one behind the left rear wheel. I asked my dealer why changing filters is a dealer, not customer task. He said it’s because of needing to remove the wheel to replace the filter. My wife said ours acted like yours before I found and replaced the hidden filter.

 

[pumasong]

Both great ideas - yes the filter body is translucent, so obvious, ashamed I didn't think of that myself. Thanks!

I'll pick up a diesel pump to see if I can clean it out if I do discover a blockage. It just seems a bit weird to me that it always takes 20 mins....

 

[pumasong]

I see someone said it but remember 2 filters, one behind the left rear wheel. I asked my dealer why changing filters is a dealer, not customer task. He said it’s because of needing to remove the wheel to replace the filter. My wife said ours acted like yours before I found and replaced the hidden filter.

Really interesting! I have no problem stripping it to get to the filter, any idea which side? Presume the right side as you sit on it as that's the side the tank is on.

 

[pumasong]

If you have eliminated overheating, like it sounds, then you need to get into fuel. If the filters are clear, then the tank is your likely problem... Probably time to pull it. It seems like most tractors and mowers start by grabbing a fuel tank and then building everything around them, so they are usually a total PITA to get at.

One last thought - is there a sensor that kills the engine on overheating? I know my Deere mower will kill the PTO if the temp climbs high enough, and it might even kill the motor if it goes farther, but not sure on that. I've had it kill the PTO a time or two when it was very dusty and I got slack about checking screens while mowing. Easily fixed by stopping and blowing it all out. >>>But my point here is that if you are not actually overheating, perhaps the sensor (if you have one) is giving bad readings and killing the motor.

There are temp sensors because there's also an over-temp alarm on the dash - but I would have thought if it got to the point it was cutting power, even if the sensor was mis-reading, it would also have lit the light.

 

[thclimer]

Really interesting! I have no problem stripping it to get to the filter, any idea which side? Presume the right side as you sit on it as that's the side the tank is on.

#1 seems to be under the tank, #2 would appear to be on the opposite side:

Messicks.com has some pretty good parts lookup diagrams:

Kubota GR2120-2 Parts

Kubota GR2120-2 Parts

www.messicks.com

 

[pumasong]

That secret filter has to be it! I will have a look over the weekend and let you know. Really appreciate the help, I wouldn't have thought there would be more than one.

 

[MHarryE]

Yes, as shown in diagram, filter is behind left wheel. Very easy to see, may be tricky handling the clamps if I remember right.

 

[pumasong]

Hi all,

Just wanted to update here to let you know what happened and also help anyone else that comes across this thread in future. Long story short - the various posters above were right on the money, it was the first of the two fuel filters, located behind the rear left wheel. I swapped out the filter and after a bit of rough running whilst the air worked its way through the fuel lines, all is well. Mowed the whole of our property without so much as a hiccup.

Notes about the process:

- The filter is the first thing in the fuel line from the tank - so you need to clamp the flexible pipe that feeds it BEFORE you remove it. Yes, I worked that out the hard way.
- An impact driver with a long extension bar makes removing and reinstalling the filter much easier. The bolt holding the clamp is partially obscured, but I was able to get to it without removing anything with a bit of persistence.

Hopefully this will save someone some time in future anyway - thanks to everyone for your support, made all the difference!