2002 Suzuki DF140 four strokes Corrosion Problems?

Problem started in the port engine. Would start and idle fine, then after running it for 20 minutes or so when you back down into Neutral it would stall. From that point on it wouldn’t idle, until it would sit for and extended time. Than next time out same issue. Well after alot of trouble shooting took to the dealer who found a port in the engine mount had totally rust throught to the point when he took it for a test ride it blew a hole in the port and destroyed the wiring harness. Dealer replaces the engine mount and warns that it is happening in the Starboard and that should be replaced over the winter. Claims a bad design resulted in exhaust getting trapped and causing the corrosion. So took it in to have the starboard engine looked at, since than they have had other 2002 engines same model come in with corrosion issues. So they took apart the starboard engine and found the same corrosion in the engine box as expected, but in addition found the Drive shaft housing completly corroded, the oil pan completly corroded. Some of these parts stay completly dry according to the mechanic and I am having a hard time understanding that the exhaust is causing this. They are going to look at the port enginge again to see if they find the same issues with the driveshaft housing and the oil pan. Waiting for a quote on repairs but having a hard time justifying dropping thousands into these engines at this point.

The dealer said this problem will start showing up in the 2002 models due to the bad design which they since corrected. They think mine since they had 1400 hours maybe be earlier due to the high hours.

So anybody else experience or hear of this issue?