MErcury 4.3 V6 with alpha 1 sterndrive problem

[duncaninnz]

My boat recently failed on returning from a trip where there was a bang and a clattering noise from the engine bay. The engine stopped and i had to be towed. On inspection the engine runs fine but stalls as soon as you put it in gear(forward or reverse). I removed the stern leg and split the lower half expecting to see severe damage but everything looks fine. I could put it in gear and rotate the prop. However the problem persists. Any guidance would be appreciated as to what the problem is and likely cost of repair.

 

[Dieter]

First thought when you mention stalling going into gear is the shift interrupt mechanism and switch. I think if the shift cable is worn or dragging it can trip the shift interrupt switch. Disconnect the switch and test going into gear. If this works then you need to dig into the shift cable and shift linkage. None of this explains the bang and clattering unless the drive dropped out of gear and was hung unless half way shifting into gear.

did you check the ujoints and gimbal bearing while drive was off? I assume engine temp and oil pressure was and still is ok?