1996 mercury 150 efi wont start

[acummins]

SN 0G304727

I have a 96 merc 150 efi that wont start. I have fought this all summer with no luck. Even dropped it off at the marina and was told it was a starter. Was replaced and still wont start. Here is a run down

This spring the solenoid went out. Replaced it and was fine for a week. One day the starter wouldnt kick the motor over. Acted like the battery was dead. Tried different battery did the same think. Tried jumping it did the same thing. Took it to the marina they cleaned the conections and got it to start. They said starter was bad. Got home it started and ran fine for a weekand then started back up. Got the new starter and still wont start.

Starter will engage but as soon as it hits it stops. I threw a tester on the battery.it is good but when you go to turn over the battery drops to 4 volts.

Idk if i have a computer issue or what. This a last ditch try,if i do t get it running im going to let it go.

[revlimiter]

Have you checked the battery cables themselves over? They could possibly be corroded internally at the ends or possibly damaged where it's not visible.

[JOE54]

4 volts wont start it, try another