83 Evinrude 50Hp won't start after running awhile

83 Evinrude 50HP will start and run fine. Occasionally after running for awhile it will not start then after sitting for a period of time will start fine again. Have charged the battery and replaced the coils. Have been told the rectifer overheating will cause this. Anyone have any answers?

Well you need to troubleshoot to discover if it is a fuel or spark issue.

While trying to start engine with no luck, remove both spark plugs, are they wet or dry. If wet tou may have lost spark, if dry most likely no fuel getting to cylinder.

This motor will have a fuel primer, the electronic valve is located on the air intake, its black and has a red twist valve for manual operation. have someone rotate the key switch to the run position (not crank) and does it make a klick noise, if it does it mostlikely is working. When you try to restart the engine when hot you may need to activate the primer under some high heat conditions, (not always)and always when engine is cold.
When trying to start warm did you try squezing the primer bulb? It most likely will have some resistance to the squeeze of your hand, if it is very soft and takes several times to make it firm. When firm try to start!
If none of this works and motor runs well when you can start it, need to check out the ign (spark)
(rule #1 do not crank engine over with no spark plugs in hole) if it does spark the plug can ignite the fuel as it sprays out the plug hole and cause a fire.
Next purchase a sparkie and follow the directions (that come with sparkie) and see if you have spark.

Try this and contact back.