Black smoke at start, then no start Kubota B7500

[bcarwell]

I have a B7500 subcompact Kubota tractor.

Everything was running fine. Then about a month ago it sat for 2-3 weeks during heavy rains. When I went back to start it, there was black smoke at startup, then it ran for 15 seconds or so and quit. In trying to start it again right then, I see much more black smoke and it won't start now.

Could you please indicate to me in order of most likely to least likely what the cause might be ? I'm hoping that at the top of the list is bad fuel maybe with some water or condensation, as the fuel was fairly old and in heavy rains and if that is the case, how do I drain it out ? Is it simply checking the fuel filter and detaching the fuel line somewhere or is there more to it to make sure its out of the tank ?

I am aware of several other possible causes: dirty injectors, timing (pump injector), plugged air inlet, plugged crankcase vent, valve adjustment, atmospheric sensor, auto timing advance, etc., etc.

But what are the most LIKELY other causes and ones that, not being a diesel mechanic, I could diagnose and check for, and ideally at least take a shot at fixing without getting knee deep in a shop manual, etc. with limited tools ?

I just want to give it a shot before calling a mechanic in out here where God lost his shoes....

Thanks for any help !

Bob

 

[kenmac]

check, replace fuel filter and bleed accordingly. That would be the easiest/ cheapest thing to try first

 

[AllDodge]

Black smoke is to much fuel or burning oil

Check your oil level to see if it has changed.
If water got into a piston then it would have busted a piston

If the injectors are removed you can see if oil belches out, or use a compression tester (for diesel) to check

 

[Mendonsy]

Also check the air filter and connections to be sure it is getting air properly. Black smoke usually means that the mixture too rich. Also check to be sure that the glow plugs are getting power when the key is in the start position.

 

[thepumpguysc]

Before u call.. check fuel filter for water..
IF the exhaust was left uncovered, there may be a chance water had gotten in?? BUT u said it ran afterwards, so either it cracked a piston or it didnt.??
Loosen the INLET LINE at the injection pump & MAKE SURE u have fuel there.. either turn on the key switch to operate the electric fuel pump OR spin the engine to get fuel WITH OUT AIR, up to the inlet of the inj. pump.. & tighten when u get it.
Next, loosen ALL the lines AT THE INJECTORS.. MOVE THE THROTTLE TO WIDE OPEN.. & crank the engine until fuel squirts out w. NO AIR.
Tighten the lines at the injectors..
Operate the glow plugs for a 20 sec. count.. even if u have to cycle the key switch to get there.. 20 sec..
Now with fuel AT the inj. pump inlet & fuel AT the injectors & the cylinders warm{assuming the GP work}.. it SHOULD start.. good luck..

 

[tvman]

I have a B7500 subcompact Kubota tractor.

Everything was running fine. Then about a month ago it sat for 2-3 weeks during heavy rains. When I went back to start it, there was black smoke at startup, then it ran for 15 seconds or so and quit. In trying to start it again right then, I see much more black smoke and it won't start now.

Could you please indicate to me in order of most likely to least likely what the cause might be ? I'm hoping that at the top of the list is bad fuel maybe with some water or condensation, as the fuel was fairly old and in heavy rains and if that is the case, how do I drain it out ? Is it simply checking the fuel filter and detaching the fuel line somewhere or is there more to it to make sure its out of the tank ?

I am aware of several other possible causes: dirty injectors, timing (pump injector), plugged air inlet, plugged crankcase vent, valve adjustment, atmospheric sensor, auto timing advance, etc., etc.

But what are the most LIKELY other causes and ones that, not being a diesel mechanic, I could diagnose and check for, and ideally at least take a shot at fixing without getting knee deep in a shop manual, etc. with limited tools ?

I just want to give it a shot before calling a mechanic in out here where God lost his shoes....

Thanks for any help !

Bob

My B7500 did the same thing , went to start it this spring and lots of black smoke. A local farmer suggested checking the air filter and lo and behold I found dead mice in the air intake. There are 2 air filters, make sure you also remove the inner air filter, thats where the mice were.
Black smoke =too rich.

 

[Ford850]

TX has had a lot of rain recently. Like others suggested, check your air filter first. It could be water-logged or be full of mice looking for a dry home.

 

[aczlan]

Before u call.. check fuel filter for water..
IF the exhaust was left uncovered, there may be a chance water had gotten in?? BUT u said it ran afterwards, so either it cracked a piston or it didnt.??
Loosen the INLET LINE at the injection pump & MAKE SURE u have fuel there.. either turn on the key switch to operate the electric fuel pump OR spin the engine to get fuel WITH OUT AIR, up to the inlet of the inj. pump.. & tighten when u get it.
Next, loosen ALL the lines AT THE INJECTORS.. MOVE THE THROTTLE TO WIDE OPEN.. & crank the engine until fuel squirts out w. NO AIR.
Tighten the lines at the injectors..
Operate the glow plugs for a 20 sec. count.. even if u have to cycle the key switch to get there.. 20 sec..
Now with fuel AT the inj. pump inlet & fuel AT the injectors & the cylinders warm{assuming the GP work}.. it SHOULD start.. good luck..

The B7500 should have a low exhaust, so water wouldnt enter unless it was flooded. I would follow tyman's suggestion to check the air intake for blockages (such as mice), then follow the instructions above.

My B7500 did the same thing , went to start it this spring and lots of black smoke. A local farmer suggested checking the air filter and lo and behold I found dead mice in the air intake. There are 2 air filters, make sure you also remove the inner air filter, thats where the mice were.
Black smoke =too rich.

Aaron Z

 

[bcarwell]

MANY thanks to you all for such prompt and thorough responses. I'll get right on it and report back, starting to check whether Mickey and/or Minnie bedded down for the winter in the air intake...

All the best, Bob