The lanyard switch is NOT part of the starter motor circuit !----There is a switch in the control box that only allows the starter to operate if lever is in neutral.---So simple.
You may have discovered your issue.----Getting parts from a good dealer is always the best.----Some online sellers will sell you just about anything !!!
You go to a hydraulic cylinder place.----Put old parts on the counter.----Say---" can you help with this "------Or find a place like-----ABLE O-RING----And see a million different o-rings / seals.