No High end power

[kenai]

I have a 2004 175 hp sportjet and it just started to have no igh end power or rpm's. It starts fine and idles fine but will not go over 40 kmh at WOT when it usually will do upto 70 kmh.

I can get it to about 400 rpm and tha is it at full throttle.

Any ideas why it bogs down.

Thanks

kenai