MEP-531AE-DEG Starting Issues

[DieselGenAC]

As I rotate the engine with the valve cover off, I have a gush of air coming out of the pushrod galley. Not good right?

It is a single cylinder engine. The air in the block displaced by the moving piston has to go somewhere.

 

[NEIOWA]

Yanmars are very good engines but don't use ether it will cause damage most likely breaking a piston ring land.
I have rebuilt 2 of these L70's that were wet stacked and the camshaft & lifters were damaged from corrosion which pitted the cam & lifters making them unusable.
90cummins

??? I thought wet stacking was only a problem in liquidcooled gensets? Running a MEP531 with a very light load.

 

[DieselAddict]

??? I thought wet stacking was only a problem in liquidcooled gensets? Running a MEP531 with a very light load.

It would be most accurate to state it as being more of a problem in water cooled diesels. Any diesel will do it if run at very light loads long enough.

 

[90cummins]

These generators are designed to operate in very hot environments perhaps 120 degrees or more in which case wet stacking would most likely never occur even with zero load.
However take that same generator and use it in subzero temperatures with no load or light load and you have problems especially with small air cooled engines that have no provisions for temperature regulation. The engines operating temperature is dependent on heat generated by combustion and the ambient air temperature.
Light load (little heat generation) and subzero air = cold operation.
A water cooled engine at least has a thermostat that maintains a closed coolant circuit which helps the engine preserve its heat but it to can be over cooled.
The military has a kit that maintains a minimum electric load to help maintain engine temperature.
90cummins