water in boat

[mario]

hi guys got bit of a problem,i have a 17ft sea nymph the one that the engine fits in a well inside the boat,the problem is i have changed engines from a 25horse two stroke to a honda 15 horse four stroke and after taking it for a hurl on lomond yesterday was lots and i mean lots of water coming over the well,tryed adjusting engine but to no avail,same type of engine ie longshaft and is lighter than first engine could it be the prop??and would it be possible to change design of well ie could it be helped with bit of perspex or similiar