Having trouble with a '96 502 Mag. Ran great when winterized, dewinterized and can't get to start. Hits every so often like it wants to start but no luck. I Have fuel pressure at the front of the fuel rail while trying to start. Changed distributer cap and rotor, coil, & ignition module, didn't help problem at all. Any ideas??

first need to know how much pressure is at the rail.....38 42 lbs is good ,..is the high pressure pump cycling ? meaning coming on when turning the key on then going off, could be injectors, plugs

Sounds like an ignition electrical issue. Go through the troubleshooting flow chart http://www.boatfix.com/merc/servmanl/16/16b4r2.pdf

throw a timing light on it. if it is blinking, it has spark.

My old 502 did that to me. Sent injectors out for cleaning, sat wile reassembling everything. No start. All test pass, fuel pressure, spark, diode test, timing. In the end I tapped each injector with a screw driver and she started right up.

Pintle got stuck form sitting with the injector cleaning solution or something like that. Asked the cleaner dude, took full responsibility for it. Said he figured I was reinstalling them right away and not going to have them sit, other wise he would have oiled them up. I here is common on the 1075's