454 to 502 engine swap reused TB5 from 454 and im having ignition problems...i think
 

Everything runs great at idle and in neutral the 502 revs rite up like it should but under load it is just not all there no backfires or anything just lacks power when planing off or at wide open. But here is the catch it only happens sometimes its intermittent and after about 45 min it becomes less frequent. So when the issue is not there the boat comes on plane like a jet ski and runs 60+mph but when its messing up its slow to plane and only hits 45 -50mph.Im thinking the knock sensor is getting a false signal ....sometimes can anyone give me some input

I'm no guru by any means so take this fwiw....
I swapped out a 1995 7.4 for a ZZ502/502 several years ago, and used the Tbolt IV ignition on the ZZ, that was on the 7.4, and it worked just fine. Can you just unplug the knock sensor or will the Tbolt V not function if the knock sensor is unplugged?

Hopefully one of the more talented members here will chime in. If nothing else, I gave your thread a bump up....

I don't see it being a knock sensor. If the knock sensor is activated it will retared the timming so you will only get about 2800 RPM which will bring you off plane, it happened to me. My first thought is its a fuel issue, your not quite getting full fuel. Maybe filter, pump, line something is not letting you have all you need.

Thanks for the help guys but I figured it out.....Here was the problem everything was working as it should except when i did the motor swap I tied all the wires up nice and outta the way and the knock sensor wire was zip tied with the spark plug wires all in one. So the high voltage current even though there were no bare wires sent a false signal to the knock module and it would retard the timing ...i rerouted the wire away from the plug wires and it hasn't done it sense I cant believe that was all it was. Thanks again !