Water Exhaust leak

"I have Crownline 202 with a 4

"I have Crownline 202 with a 4.3L Mercruiser Alpha One IO. When in the water there is a noticeable dripping leak from someplace behind the engine. When the engine is off. When running, the leak is greatly reduced or even nonexistant.
All 3 bellows have been removed and checked.
When running on a hose with earmuffs, there appears to to be exhaust water and gases coming from the area behind the shift bar just above where the mating area of the upper and lower unit.
This area also dribbles water on the hose with the engine off.
The outdrive oil is fine, and the resevoir never drops. Engine temperature is normal.
Any ideas are greatly appreciated.

T.I.A.

Steve"

Steve:

Not leaking when u

Steve:

Not leaking when under way could mean it is a damaged seal. Does the bilge take on water when it is sitting in the water and not running?
Can you hear loud exhaust in the engine compartment when running in the water?

Bellows are checked ok; maybe "Y" exhaust pipe gasket is damaged. Does the engine run smoothly w/o rough idle? Get an extension handle mirror and bright sealed shop light to see under the rear of the engine.

Guy

"Guy,

Yes, when in the wat

"Guy,

Yes, when in the water and not running it takes on water rather quickly. After 20 minutes or so the water level is near the bottom of the oil pan. With the engine running, whether moving or simply at idle, there is no noticeable increase in the bilge water level.
I don't hear above normal exhaust noise from the engine compartment and it starts, accelerates, runs smooth.
Would you know expected cost of repairs for a seal or Y joint? Is this something a mediocre mechanic can do?

Steve"

"It sounds to me like you need

"It sounds to me like you need to get down under there with a flashlight and mirror and try to pin down exactly where the water is coming in. If it is the Y pipe, you will need to remove the drive leg and the motor completely to replace it.
It's unusual in that the common problem is the water level rises quickly when running, and not so when shut off. That usually means a leak in the inlet cooling water system somewhere.
Rod"