2000 H2X with 7.4 mpi issues
 

I have a baja H2X with 400 hours and a mirage plus 23 prop. The boat has been starting hard I have to give it some throttle to start it and keep it going also the boat is topping out at about 50 mph and will not rpm past 4000 rpm's any ideas?

Possible?
 

You may want to verify if you have any water leaks at the exhaust manifold/riser gasket joint or head gasket leak? Check your oil for any signs of water.


You may want to perform tune up wires, plugs?

I would do a compression check that may telll you alot for no cost to you but your time.

Thanks. Took boat in to get it checked praying it is just a tune up issue

What engine? Is it fuel injected?

If it's injected check your fuel pressure and injectors. Clogged or poor performing injectors can cause the same issue. Usually it leans out a cylinder or two and it starts to detonate. Once that happens timing gets rolled back compounding the problem. If not corrected worse things start to happen in the combustion chamber.