I'm just going over things on my 1984 5.7 Mercruiser just prepping for Spring. I noticed inside the distributor the advance sensor is rusty looking. I tried to remove it for cleaning but it appears the shaft must be removed before the sensor can be taken out. I'm just wondering if the sensor needs replaced. I have been experiencing a bad hesitation problem for two seasons that I've been unable to solve. Could this be the culprit?