93 50 Cobra alternator issue

"Last week I had an issue with

"Last week I had an issue with the boat. Put it in the water and it cranked over but would not start. It was getting fuel. Finally after 15 minutes it started but ran very rough at low RPM's. Got it up to operating temp. (140) and it ran pretty good for 5 minutes. Stopped for a moment but it would not start back up. Battery did get low after some cranking. Towed it in, got it home, tightened the alternator belt to about 1/4" play and it started right up everything was fine. Today took it out, it started right up ran great for 5 minutes at around 3600 RPM, stopped and it would crank but not start. Checked for fuel, OK, alternator belt seamed to have the right tension, Towed in, got home tightened the alt. belt agian it started right up. Does this sound like an alternator issue, battery issue. I checked the voltage reads for the alternator and they were equal to the battery. What do you think the issue could be?"

"Try it this way, if you have

"Try it this way, if you have a gauge, turn the key to on, voltage gauge reads xx, start motor, voltage gauge should read higher.
nominal charging voltage is around 14.6
With no dash gauge, hook a meter to the battery ,read voltage, start motor, voltage should increase"

Thanks for the input. Voltage

Thanks for the input. Voltage did increase when motor ran. Alternator casing very hot to the touch when motor is at operating temp (140) Is this normal?

"You stated it ran good for 5

"You stated it ran good for 5 min. at 36oo rpm, stopped then would not start. Did you stop and shut the engine off and tried to restart or did the boat stop on its own.The Alt. casing is going to get hot, but not extremely hot, check connections at back of alt. also at the ignition coil"