Did you make sure when you did the oil change, to confirm that the two piece oil filter was there?

Did you also clean and change the oil in the air filter?

Did you also change the oil in the injection pump?

Loosing oil in this model can be a result of the vacuum pump having a bad diaphragm, if this is bad....it will suck the oil right from the engine...

There is also a diaphragm in the governor on the injection pump, if this tears you will notice smoke, high idle and leading to a run away engine symptoms..

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