TR,
There are some "BASIC TENET" for setting up tunnel hulls. I'm sure someone will list any I miss:
1. The boat should have a balance point 1/3 of the distance from the transom to the bow. On a 27" hull, that would be 9". Place lead on the sponson tips or under the cowling chin to achieve the balance.
2. The center line of the prop should be even with or above the bottom of the sponsons. I run some of my 3.5s as much as 1/4" or more - depends on the boat.
3. A good propeller is the Octura X440.
4. Make sure the radio box is water tight. With a tunnel boat, it's "if you flip, it's when you flip."
5. If all else fails, read the directions included with the boat. I guess I'm assuming there were some instructions.
Jerry Dunlap