Most commercial mechanical products require some adjustments and replacements at regular intervals.
Cummins Onan generators are no exception, they have a service plan written for them which allows their products to perform at their maximum as well as maintaining their reliability.
One of the problems we have encountered is excessive valve clearances on the 3.6 and the 3.3KY microlite range. The result of this has been the failure of the valve spring retainers. With excess valve clearance, the valve spring lock, part number 0110-3914 can move excessively, this in turn causes excess wear as the softer material of the valve lock against the hardened poppet valve stem. The result of this is that the valve spring retainer 0110-3700 is now allowed to push the valve spring 110-3701 over the intake or exhaust valves 110-3486.
With the Cummins Onan generator KV and KY range only being single cylinder the generator will not start or will just stop, when this happens the blame will be pointed at the product, not the owner. If the service schedule is adhered to, problems like this will not happen and costly situations can be avoided.
The valve clearances should be checked and adjusted if necessary to 0.002 inch every 500 hours in conjunction with the fuel filter.