Honda 99 2006 water in idle exhaust port

I have a 2006 9.9hp on an infl

I have a 2006 9.9hp on an inflatable. It is rated for 15hp but with the 92 lbs from the Honda the low idle above water exhaust port is only slightly above the water. If I step to the rear of the dinghy I hear water going down the tube as it is under water. When I start it after that I get small amount of smoke out the engine.
How can I raise this idle exhaust port? Will this ruin the engine if I continue this way?
Thanks
Al

"Engine ratings on small boats

"Engine ratings on small boats (ala the original 13 ft Whaler) are often limited by the weight on the transom as the absolute HP. At the risk of another few pounds, I'd build an extension to the transom raising the engine a few inches. Be sure to use marine plywood, coat/saturate it with penetrating epoxy and use S/S (at least six )bolts and washers under the nuts(nyloks!) and heads. If possible, I'd extend this all the way down to the bottom of the existing transom. Use same thichness ply as existing transom. You could use a double thickness for that portion of the extension that expends above the present transom. Glue and screw that part to the larger board."

raise the puppy asap

raise the puppy asap