Kubota D1105 3 cylinder in a lawn mower will run away if I let it. It cranks and runs without turning on the fuel. It has 350 lbs. per cylinder compression. Does anyone have a clue as to why this is happening?
I lowered the engine oil to the add oil dot, did not help one bit.
A little history, this pos came to me with a broken crankshaft, which wiped out the bearing cases. I installed a set of good cases, a reground crank, new rod and crank bearings, new rings after I broke the glaze on the cylinders, which measured with in wear tolerance, and all new seals.
Right now I am thinking that I might pull the engine and try a different brand of rings.
Sorry for the delayed response as I have been under the weather.
The pos update. Thanks for all the input. I don't know why I do and do not do somethings. I purchased a valve spring compressor, pulled the injectors, turned by hand the engine over and replaced the valve seals on each cylinder.
I put it all back together and when I cranked it over to bleed the injectors as soon as I closed the last injector nut it fired up and took off just as before.
More info I have convinced myself that it is the injector pump, why? When I got this pos the injector pump rods were stuck in the compressed position. I removed the pump disassembled, cleaned and replaced all seals. I have now pulled it turned the rods around 180 degrees and as should it pumps no fuel. I then installed the rods as per spec. and it fires up and runs wide open.
The owner said he had the pump rebuilt, I could see evidence of this work. The owner does not remember if it ran on this rebuilt pump.
I know the slots in the rods meter the fuel based on the racks position. When it is running I can stick my finger in the throttle hole and move the rack back and forth with no change in the running. So, the question of the hour is could the rebuild guy have put the wrong rods in the pump? How would I determine the correct rods? I do not want to throw more money into this thing by purchasing a pump. Anyone with a loaner pump?