Engine RPM problem on my BX24

[rnbrn21]

I'm having a weird problem with my BX24. After I have been using it for about 45 minutes at a continuous high RPM while brush hogging a field the RPM's will suddenly drop off. It doesn't die it just drops RPM's to about 2000. When it happens I turn off the PTO and bring the RPM's down to idle with the throttle and let it idle for a minute or so and then bring it back up to high RPM's and go back to mowing. I can't imagine what would cause the RPM's to drop, anyone with an idea?

 

[Tx Jim]

Have you changed fuel filter lately? I recommend checking fuel flow from tank to injection pump. If problem isn't fuel related then I'd guess governor malfunction.

 

[rlsmith]

It sounds like it is starving fir fuel, so I would start with replacing both fuel filters. When you idle it can catch up for awhile again. Either that or a weak fuel pump.

 

[Tx Jim]

From viewing the parts schematic the fuel filters look similar in size to an inline gasoline filter on older auto's/pu's. i thought of something else to check. Check the fuel tank vent or fuel cap to determine if it's venting.

 

[rnbrn21]

I can understand how the fuel filters could cause this problem and I will replace them but I have a question. Are diesel engines more prone to needing fuel filters replaced then gasoline engines. I haven't replace a fuel filter in a car in 35 years, they just don't seem to go bad, are diesel engines different in this regard?

 

[DDM84]

You fill your car at a gas station and that's it. In most vehicles you cant even syphon gas out of the tank. With tractors you fill a jug or a tank with diesel at the gas station that can be opened to dirty air or other contaminants. It sets longer before use in your tractor. Your tractor's fuel tank is wide opened to contaminants when you remove the cap. And I can't think of too many areas that a tractor would be that is the pinnacle of cleanliness to fuel it. So yes a tractor will need the fuel filter changed many more times than a car.

I don't believe that your tractor has a bleed screw to let out air from the fuel system but if I am wrong that is the first place to check. After changing fuel filters check the fuel hoses for small cracks or holes as they will show themselves in the way you described. Good luck!

 

[Tx Jim]

050 is the air bleeder screw

 

[radioman]

I think with all fuels there are issues. regular gas gums up carbs when sitting for a long time. Ethanol has tendency to absorb moisture. Diesel tends to have microobes growing when sitting too long. I wouldnt overthink it and blame the diesel unless you keep large batches in a tank and it doesnt get used much. Just make sure you keep your diesel fresh and you may have to have it treated. You could have water or microbes (algae or fungus or mold) growin in your tank or can. Its only a guess right now, but its best that you get it tested to know for sure so you can take the right action.

 

[mkoehr]

I can understand how the fuel filters could cause this problem and I will replace them but I have a question. Are diesel engines more prone to needing fuel filters replaced then gasoline engines. I haven't replace a fuel filter in a car in 35 years, they just don't seem to go bad, are diesel engines different in this regard?

I just replaced mine after barely 6 months since the last replacement (i posted about this about a week ago; I was suspect of the filters getting gummed up after such a short period of time). I think over time sediment can accumulate in the tank, and work its way into the lines. I'm planning on replacing mine on the same schedule for oil changes (which I do every 6 months or so).

 

[rnbrn21]

So I went over to the Kubota dealer today and bought 2 fuel filters because I didn't want to wait for the ones I ordered online. I was skeptical that that was my problem but it sure couldn't hurt. I started with the one at the engine and replaced it with little fuel spillage and moved on to the one under the tractor. I'm about ready to pull the hose leading up to the engine off when it occurs to me that gravity might cause a great deal of fuel to come out when I take this hose off but I decide to go ahead. I pull the hose off and get a slow but steady stream of fuel out of the filter and I think well this isn't too bad. The pull the hose off the other end of the filter and to my surprise I get a gush of fuel at the volume the hose can produce and quickly cover it with my finger. So there is no doubt in my mind that the filter was indeed very clogged and most definitely was my problem. Taking a closer look at the old filter shows it to be very dirty and when I drained it actually got particles coming out. I haven't used the tractor yet but I'm sure it solved my problem. Thanks to the forum for the diagnosis. How do you all stop the fuel from pouring out when you remove the filters?