B7800 will not run after rain?

[Old Kubota]

Had a lot of rain the other day now my B7800 will only run for about 30 sec then shut off and will not start again until it sits for a little while.

Right before it dies black smoke comes out, i put in fresh 5 gallons of fuel it's doing the same thing.

The Water Separator at least that is what it looks like is not clear anymore so you can't see inside it. Could it simply be that? I haven't tried to empty it whoever put it on last used a pipe wrench. lol

I need to buy a new one.

 

[Mendonsy]

Another possibility is that the air filer got wet and isn't allowing enough air into the engine.

 

[Ed ke6bnl]

Had a lot of rain the other day now my B7800 will only run for about 30 sec then shut off and will not start again until it sits for a little while.

Right before it dies black smoke comes out, i put in fresh 5 gallons of fuel it's doing the same thing.

The Water Separator at least that is what it looks like is not clear anymore so you can't see inside it. Could it simply be that? I haven't tried to empty it whoever put it on last used a pipe wrench. lol

I need to buy a new one.

When I got my b7800 from the neighbor after sitting for 6 years outside, we put fresh diesel in the tank and it started right up ran for a few minutes and turned off. we disconnected the fuel line to the filter and let it just drain for a while and the water in the tank just drained out and has never acted up since 2 years now. just a thought. drain it at the fuel filter and drain and clean the fuel filter.

 

[Old Kubota]

I checked the air filter it had a nest in it, drained the Water Separator and it will not start.

It turns over just no start. It ran fine the last time i used it before it rained.

 

[sandman2234]

Most likely when you emptied the fuel/water separator, you introduced air into the system and now it will probably need bleeding before it will run. Hopefully your starter and battery are in good shape, as bleeding a system is never easy on them.
David from jax

 

[Ed ke6bnl]

Most likely when you emptied the fuel/water separator, you introduced air into the system and now it will probably need bleeding before it will run. Hopefully your starter and battery are in good shape, as bleeding a system is never easy on them.
David from jax

My understanding is the lift pump is manual and runs off gear in engine. When mine had water after draining water I did use starting fluid(not saying to do that) if not comfortable with that you will need to open your injector lines and crank till air is removed from lines and tighten and hopefully start.

 

[sandman2234]

My understanding is the lift pump is manual and runs off gear in engine.

You could be very much correct, however... if the lift pump runs off the gear in the engine, then it requires a good starter and battery to get it to turn over if the engine won't run.
Don't run the starter for long periods, as they get hot very quickly and take a long time to cool off. Patience, patience and then more patience when trying to bleed a diesel system!
David from jax

 

[Old Kubota]

Most likely when you emptied the fuel/water separator, you introduced air into the system and now it will probably need bleeding before it will run. Hopefully your starter and battery are in good shape, as bleeding a system is never easy on them.
David from jax

How do you bleed it?

 

[Ed ke6bnl]

When I blead the injectors on Diesels on my old Ford tractor and my Dodge diesel 24 valve that I have now. I open all the nuts on the injectors and crank it over and while I'm cranking if I see fluid fuel coming out of the injector I close it down and I continue doing that without over running the starter until they're all flowing fluid. then I would in this case make sure that the glow plugs are firing up and the tractor should start up. It is possible it will start when you have the majority of the injectors, then tighten the remaining injectors and it will run ruff and straighten out

 

[sixdogs]

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.

 

[Old Kubota]

Is this right? Seems kinda silly or missing some info. I don't have the book just found this online.

 

[Ed ke6bnl]

That is what my book says, not very clear on what is going on BUT fill tank with fuel is a big part of the procedure

 

[Old Kubota]

I can't even get it started. Battery is weak from trying but even with a jump starter it still just turns over.

Not sure what to do since it started and ran for a a min then died.

If it was anything else i would check for a spark.

 

[Carl_NH]

When you installed the new fuel filter, did you let the small canister fill with diesel before tightening the bowl? That eliminates any air in the system, and if you did not do that, yes, the engine will run until it pulls that air in, then you need to crank it to remove it.

You could still crack open the fuel filter and make sure there is no air now and there is good fuel flow, but you either need to crank it over to get the air out of the system. I would try the crank method before loosening the injector lines - that's a last resort.

 

[Old Kubota]

When you installed the new fuel filter, did you let the small canister fill with diesel before tightening the bowl? That eliminates any air in the system, and if you did not do that, yes, the engine will run until it pulls that air in, then you need to crank it to remove it.

You could still crack open the fuel filter and make sure there is no air now and there is good fuel flow, but you either need to crank it over to get the air out of the system. I would try the crank method before loosening the injector lines - that's a last resort.

Actually when i removed the small canister diesel fuel never stooped flowing the bowel was full by the time i got it back on.

 

[Carl_NH]

So you replaced the filter without shutting off the fuel, I guess? That eliminates air and its not leaking any now after replacing the filter?

 

[airbiscuit]

Here is a pretty good video about the fuel cutoff solenoid. He shows how to prime the engine at 20:50

 

[Old Kubota]

Okay i got it started didn't do anything to it, the 30 amp fuse was fine and i can hear the solenoid turn on. Looks like it had been replaced at some point as it was the cleanest part in there.

I bought this tractor off my neighbor last year for real cheap almost free with 600hrs on it and i told him what it was doing and he had the same issue after it rained and never could figure it out. Had it at the local dealer and they said nothing was wrong with it.

I did noticed that black smoke came out when it did start as normal and before nothing was coming out of the exhaust when it would just turn over and not start.

It's been outside it's whole life.

 

[Old Kubota]

Does anyone have a idea of why it does this? It has to be a good amount of rain, it rained 3 inches the other day.

 

[Carl_NH]

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!