Rebuild motor question.
 

I have a 19.5 Scarab jet with a 4.3 Volvo jet drive. I have had the motor rebuilt to stock with 60 over pistons. I have added a Ederbrock performer intake and Ederbrock 1409 marine carb. The boat runs fine with the exception of it only runs 4000 rpm at WOT. The throttle has ¼ left to go but no gain or change in speed or rpm in the last ¼ throttle. I know ederbrock recommends using a smaller jet, metering rods and spring with the carb on a 4.3 motor. Could this be why im 600 rpm short of where I should be or is there something else to check.

Thanks
Speed

tried the smaller jet and it runs rough at around 2000 rpm???