engine height

[Joker2]

Thanks, should I worry about the space there will be between engine bracket and the top of the transom ? I had my ear to the motor while running 3,000 RPM and I hear what sounds like a rattling, sounds like it is coming from the lower unit, could there be something going on down there to cause me not to get my full RPM's. I am still trying to find out why I can't get my RPM's (only 4200 ) my prop is 15-1/2 X 15 dinged up a little ( Alum. ), the engine is a little low, I checked all carburator items, all OK, could it be a combination of all these things ? what could I do to check out the lower unit ( if anything ) ? Thanks