I have a 2002 396 that I recently purchased and, as I understand, hasn't been run very much in the past two years.

I had the engines inspected by Cummins, oil changed, etc. Both starboard and port checked out and ran like monsters.

When I first took her out, I could easily do 3000 rpm and make 20 knots. The throttles were uneven when synced, but that didn't bother me too much at the time. Not to mention, the sticks were only at about 3/4 throttle. I had plenty more room to go.

As a few weeks went by, I noticed I had to push the throttles more and more forward to get more speed. Pretty soon, I had the "balls to the walls" and I was only getting 2500 rpm and making only 16 knots. And now the sticks are even when synced.

My marina mechanic thought for sure it was fuel filters (I thought it that was a good idea as she hadn't been run or cared for for two years) He changed the filters and took her out and experienced the same problem... but didn't know what else to do (great mechanic, aye?)

Anyone have experience with this problem or have an idea where to start looking for the problem?