To quote JohnS...Well I have to disagree with not opening up an engine if it is not broken. because Q/C is all but non existent and assuming the builder did a good job is a mistake. I open all my engines up and usually find something like this going on. future mishaps can be avoided by correcting them early on. it takes some skill to open up an engine, but not much.
I completely agree. Out of all 11 of my ps3 and 2 engines 7 needed some attention from repositioning wires to defective 2rail 3 rail switches. I now pull the cab shell and inspect and service before it sees the track.