Kubota B7800 - hard starting, lots of smoke, low idle

   / Kubota B7800 - hard starting, lots of smoke, low idle
  • Thread Starter
#11  
Update: Started it this afternoon after sitting for 2 days. No problems, just a touch of black smoke at the very start then good throttle response across the range. The tank was about 1/6, so it is possible that, if there is a leaky injector, the fuel tank did not have the pressure to push out fuel as it was sitting.

I filled up the tank, and included some diesel injector cleaner in the 5-gallons. I will probably use her some tomorrow and Sunday, and if all goes well I will top off the tank and see if I get the same bad start/black smoke after sitting next week.
 
   / Kubota B7800 - hard starting, lots of smoke, low idle
  • Thread Starter
#12  
Update: Ran it today. Started right up and had no issues pulling a landscaping rake around a riding arena.

I did take a closer look under the hood as I checked the oil, and noted that the muffler weld had broken where the muffler is attached to the down pipe that hooks into the exhaust manifold. Quick look on Mesnicks, and a replacement muffler is $450...lol. When I have the opportunity, I will pull the muffler and take it to a local welder, and he should be able to reweld it for $40. I do not think this had anything to do with the issue I had....unless somehow the muffler shifted and blocked exhaust gases for a period.
 
   / Kubota B7800 - hard starting, lots of smoke, low idle
  • Thread Starter
#13  
Here is a picture of the broken muffler (I was wondering what that rattle was under the hood). With the relatively heavy muffler sitting on top of that single exhaust pipe, with no other support, it is not a surprise that after 800 hours the weld would shake loose. I will ask my welder to add bracing on either side (exhaust pipe to underside of muffler) to give that point more support.

Started up good this morning....nothing leaked on the driveway overnight, so the original problem is still a mystery.
 

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