97 Challenger won't rev past 4500 RPM

[wilsonii]

A little help

I recently replaced the motor in my Challenger with a new SBT Prem 787.

I'm able to get it to rev up to full throttle and jump up on plane for about 15 minutes or so by throwing the throttle from 0 to full a couple times but every time I let it drop down near 5K it just stops at 4500 and won't go past again with out doing the same thing / This works fine for 15-20 minutes

After that I can get it to go back to full throttle by throwing the throttle from 0-full a dozen or so times then after 30 minutes or so i can't get it to go back to full throttle at all and end up limping back to the marina at 4K

Rebuilt the carbs, changed the fuel filter and replaced the throttle cable / thought maybe it was stretched...

Still does the same thing.

Give me an idea where to go from here...

 

[timmyboy76]

the raves clean? Did you replace the spring inside the carbs?

 

[wilsonii]

Don't know on the Raves

The dealer did the rebuild on the carbs for me - I figured a tuneup would fix the problem so i had them rebuild both carbs and "Tune it up" still does the same thing though

I'll look at the rave valves to see if they cleaned them