Tach wire no start

[Estarnes67]

93 omc cobra 4.3...going down the lake boat stalled. No spark. Took the tach wire off no change. Changed coil no difference. Took the tach wire off on new coil and it fired right up. While running tried to put tach wire on and it wanted to stall. I dont believe the esa module works which the tach wire goes into. Push the esa arm on the linkage nothing happens.Do you guys believe the tach would go bad itself or the esa module took a **** first? And maybe took out the old coil? Anyone have a link to test the module? Or a better way to look at this?