Motor is a 383 with a weiand 144 blower. Of course it did not do this before the blower. When cruising or at WOT you can feel the boat slow down and the motor sounds like it is loading up or something cause it will bog down alil then it cleans up and takes off again. Stock thunderbolt ignition with total advance set at 28* for the blower as recommended by weiand. Plugs are NGK tr-6 gapped at .032. I checked the wires and made sure they were connected good. It just started doing this today. Was fine last weekend. I am leaning towards ignition problems. Gonna start with a decent 8.5mm wire. Any other ideas?

Thanks

Is it possible you got some bad fuel and or your fuel/water separator filter needs to be replaced? Is the "loading up" kind of like its dropping a cylinder for a few seconds?

could be running rich, maybe give it more air or lower jet size

What do the plugs look like?
How long has this set up been together? You might have to tune it some more.

pulled all the plugs. Found one plug gapped almost 100% closed. I must of forgot to re-open it when I gapped them down. Re-gapped them all to the correct gap and now all is good.

Might want to check for signs of detonation. I don't know how detonation would close the gap on a plug but I have read about it a few times.

Glad to hear it was an easy fix.