Engine cutting out
 

2007 indmar MCX
Boat starts and idles fine. Takes off great. Smooth powerful. Then loses power. You have to pull throttle down to idle speed then give it gas and it takes off again. It used to do it intermittently, and not at high speeds or with boat loaded down. But now does it everytime. We've taken air filter off and watched the throttlebody flap close when it does it. So something is telling it to close. We tried holding flap open and it bogs and misfires. Then turn Boat off and it runs fine and goes through same process.
Things I've done or tested.
New fuel pump and filter
Fuel pressure fine all the way through problem.
Changed MAP sensor
Changed TPS sensor
Changed throttle cable
New throttlebody (did samething so returned it)
New ignition switch (key)
Checked for bad grounds and corroded wires
Changed oil & filter 😂
I've taken battery cables off each time to clear ECU

Local shop with MEFI computer is booked til Aug 17. So I can't tell what codes are popping up.

One note. My medallion 1600 dash gauge brain is toast so I can't see readings. But I've used it many times this summer. And nothing has overheated or seized up.
Thoughts?
Thanks for The help I just resubscribed here
I was on here back in the day when it was just a forum been reading a lot of on here
thanks again

I would take the cap and rotor off and look at the points. Mine a couple years ago started bogging and it sound like a miss fire at times. I thought I had bad gas but when I took the cap off all my point where corroded.

It's Indmar, do they have their own software? I know Merc does...

cap and rotor for sure.

check your fuel pressure when bogs down. hook up a gauge and go run it, see if it drops. a lot these boats have 2 fuel pumps. sounds like a fuel delivery issue

I know this sounds out there, but it could be a bad oil pressure switch. If it's going intermittent and not staying open or closed(depends on your model engine) it could be putting itself into limp mode. If it has an oil pressure switch it will be down above the oil filter on the side of the motor. The oil pressure sender is up on top usually around the distributor. If it does have the switch you can try unplugging the wire to it and see if it clears up and runs. If it doesn't you may have to ground the wire and run it and see if it clears up. But either way if it clears up and runs without the wire or with it grounded, your problem lies in the oil pressure switch. Also if it has two wires touch them together and se if it clears up.

Just FYI Rinda Technologies sells a code reader for about 100 bucks. It's nice to have. I'd change the plugs and wires too. Good luck!!

Friend of mine had a similar but not identical issue for a couple years and it ended up being the plug wires. New plug wires, Runs like a champ now.

Yea, you didn't mention plugs, wires, cap and rotor....the normal wear items. Any of those items could cause that issue