B7500 black smoke.... ah, MAINTENANCE

[theboman]

It has bothered me for a while now. The little 'Bota B7500 working it's tail off, and it gets in a bit of a strain and a puff of black smoke rolls outta the muffler.. The baby 'Bota just keeps on mowing, bush hogging or whatever and no complaints...But that smoke kinda worries me.

I'm pretty good at keeping the oil changed somewhere every 50-100 hours...

After a couple of hours of mowing the grass it's time to blow all the dust/seed from the radiator and it's screen and decided it's been a LONG time since I cleaned the air filter... OH MY GOODNESS!!! It looked like a back outta my wifes vacume bag, plum full of dust and dirt....

I beat out the dust and blew it out with the compressor and low and behold the black smoke stopped!!! I owe my 'Bota an apology for being neglectful.

CHECK YOUR AIR FILTERS!

 

[Egon]

The experience is not unfamiliar!

 

[AceDeuce]

Black smoke in diesel exhaust is symptomatic of a condition called "overfueling". Basically, the "black" is soot which results from unburnt fuel or incomplete combustion. It can be expected on startup and when your engine is under load but modern diesels don't smoke under other normal conditions. So it shouldn't indicate a problem unless your engine smokes constantly or when it is idling. If it does, a fuel pump, timing or valve adjustment might be necessary.

 

[Egon]

If insufficient air gets to the cylinder could that not be considered as over fueling??

 

[Volfandt]

Fer shame Fer shame
Poor little engine was just staving for alittle air and that was it's only way of tell'n ya, besides just stopping dead in it's tracks

Seems I recall reading here awhile back where some interprising sort clamped on a short extension to the muffler on his B (7510 or B7610) so it would aim down and away further from the engine compartment and the soot would blow away instead of on his cowlings an into his intake.
Anyways any easy fix is a great fix

 

[DiezNutz]

If insufficient air gets to the cylinder could that not be considered as over fueling??

Yes, exactly. If the clogged air filter creates enough suction you'll also start sucking oil past the valve guides and rings. None of this is very good.