2001 250 hp OX66 - #5 Cylinder will not fire

[FlyingWhale]

Recently had regular service that included new filters, plugs and a fuel injector cleaning. When water tested the engine would shut down as soon as 3/4 throttle was reached when accelerating. Found acracked fuel pump diaphram and went ahead and replaced all of them. Water tested and now engine can't get above 5000 rpm and it appears #5 cylinder isn't firing at ant rpm. Any suggestions as to the cause.

[99yam40]

Check for spark with a timing light , but more than likely it is an injector so be careful. If running lean it will eat a piston