Boat starts runs fine. Idle out of canal fine gets on plane runs great. Run along 3800 rpm perfect. As soon as I let off at all starts breaking up. Then continues the bog worse and worse. At idle barely run. Leave it for 20 mins starts up runs fine again for a while then same issue. Changed seperator and in-line filter no better. Holley 750 double pumper I’m thinking loading up?

Float valve in carb not sealing ??

Have you checked your spark plugs to see if you are getting excess fuel? Could also be you coil over heating, had that on my boat, did the exact same thing.

its weird bc I’m not seeing any heavy smoke or smelling excess gas. I’ll swap coil cheap enough

The first hiccup I had was around 4K was getting a little miss. I thought I was hitting bottom just little shutter. Let off then ran like ****

I have the Mallory electronic ignition and a super stock coil. I looked it up, the ignition requires min 1.5ohm. The super stock is 1.4ohm. I ordered a new coil fingers crossed it’s overheating. Boat runs absolutely perfect then acts up. Limped to trailer ramp on 4cylinders lol. Got home started it to flush it ran perfect.

May not be the issue but a very similar thing happens when the fuel tank vent is blocked .
To eliminate that possibility loosen off the fill cap and try running it as you do when the problem presents itself.

Thats exactly what I was going to do next time out. After it acted up, I opened cap tried listening for sucking air but was windy. Weird bc cruised at 3400rpm for a couple miles no issues. Soon as I pulled back just 200rpm it started acting up and got worse.

Looks like I’m loading up on the primaries

Has me thinking I’m fine when running on secondaries, let off a little and acts up. Primary side of carb all black