120 L-Drive Leak exhaust/water inside

[tonyapb123]

I have a 92 force 120hp L-Drive. It is leaking exhaust and a water from what it looks like the gasket between the block and transom connection, near the aft engine area, down near the mounting clamps. The exhaust fills the engine compartment area. But, it does not happen while starting on land, when I test start before I go to the ramp. I happens only in the water, after running for 30 sec or so. I assume that he back pressure from the in the water enhances the leak. The engine also becomes sluggish and stalls 95% of the time when advancing the throttle. Question: Is it just a matter of replacing a gasket, or is it more serious? This engine has been running good for the last 15 yrs and I'd like to get a couple more out of it.