B7800 will not run after rain?

[Carl_NH]

You are fortunate to have a known machine, so inquire when they last did the major service? Typically (300 hours) is Hydraulic SUDT and Filters, Engine oil 50-100 hrs, and air and fuel filter is check/clean at 50 hours and replace at 200.

Depends on care and condition - if stored outside, sounds like it has had a tough life so far. It will treat you well if you do the basic maintenance and keep it out of the elements.

 

[Old Kubota]

OK so it started now with a puff of black smoke, which is normal in the first few seconds after starting.

I suspect it was the plugged air filter, when its wet / damp the pores of the filter are so plugged it can't get air - though its rare, it is possible if you are in a damp, humid environment and have dust too - this will then grow algae inside further blocking the air.

Mendosy said "Another possibility is that the air filter got wet and isn't allowing enough air into the engine" I think it the best diagnosis I can see from my limited view!

I cleaned out the air filter and it was not wet, it had a nest built up around the filter and another below the engine and another in front of the radiator!

Makes me wonder if one can get past the air filter clogging it up.

 

[airbiscuit]

Time for a new air filter

 

[dbritt]

I hada B7800 and bleeding the system was very easy. Look in the owner's manual for instructions because I don't remember. Don't start fooling with lines till you try the easy things.

One big thought is that you must have more than a half tank of fuel in order for the system to bleed on it's own.I forget the details so check the owner's manual.

EDIT---Something else I know is that the fuel lever you turn when you drain the water filter has to be turned to do the job. It WILL turn 360 degrees and you turn it 180 degrees ONE WAY to close the fuel. When you turn it back, you must reverse the turn you made and not continue around. You can, in error, turn it it full circle back to where you think it started from but it will partially restrict fuel and not run for more than a minute after starting. The answer is to turn that lever back. Maybe you did this?
Now, it's been a while so I may not remember all the turn degrees correctly but know to just turn the lever one way to close and fuel and turn it back the way it came to open things up. I mad this mistake and spent a while trying to figure it out. Don't fool with lines and stuff because Kubotas are made to bleed lines on their own and bigger problems can be created. Kubotas are almost foolproof.

The information about Kubotas not needing to be bled is not a universal statement in regard to Kubota. My M9000 has to be bled every time I change the fuel filter or clean the water trap. The manual has the procedure for it detailed in the maintenance section. It IS much easier than my Ford 3000 or NH TC-33D (both of which are a royal pain in the patoot), but it will not start until I go through the procedure in order. Maybe the compact Kubotas are different.

 

[sixdogs]

The information about Kubotas not needing to be bled is not a universal statement in regard to Kubota. My M9000 has to be bled every time I change the fuel filter or clean the water trap. The manual has the procedure for it detailed in the maintenance section. It IS much easier than my Ford 3000 or NH TC-33D (both of which are a royal pain in the patoot), but it will not start until I go through the procedure in order. Maybe the compact Kubotas are different.

That is true. My M8950 was like your M9000. Great tractor by the way. Still way easier than most things out there.

In recent memory, all the smaller Kubotas are E-Z bleed. I remember doing it by the owner's manual on my B7800 the first time and it was so easy I thought I missed something.

 

[Old Kubota]

apparently there is no shut off valve.

Service Tip:

Be aware there's no built-in fuel shut-off, so it's wise to have a catch basin ready to manage any fuel spillage during the process. Some mechanics suggest using a sharpened pencil to temporarily stop fuel flow when disconnecting the feed hose, making the job cleaner and easier.

 

[Old Kubota]

Time for a new air filter

Brings up another point. Kubota filters are costly.