Motor Trouble

[Hunt2Fish]

I am creating this post for some advise.
I have a 2001 Mercury EFI 200 HP that will not take off. Meaning that when I give it the throttle to go, it will not. It acts as if it is bogging down on the load. I have poured nearly $4k into this motor trying to solve this issue. The motor itself is strong. It starts up and idles great. My first mechanic did many of the items that is listed. He asked me to get another opinion because what he did wouldn't work. My second guy cleaned the injection ports and tested all injectors. Which all tested fine.
All includes new wires and plugs, new stater and switch, new CDI box, new fuel pump, new fuel lines, new computer, new filter, new ESM and just over the weekend new cables and hot foot.
I am at my wits send with this trying to figure out why it will not go.
Any thoughts?

[EuropeanAM]

Moving your post to the correct (2.5L) forum. If you would, please take a moment to review the Announcements at the top of the Forum, and be sure to provide the Required Info (serial number) when posting. Thanks!

Please give a short version of detail on PRECISELY what you do when starting the engine, through the time you hammer down on the throttle (and precisely what the engine does or does not do then).

Also- if someone moves forward in the boat does it finally get on plane and run halfway decent?

[Hunt2Fish]

The short version is that when I start the boat, it starts up just fine. It will idle great as well. It is when I give it full throttle to take off and to get on pad, it will not. That is when it bogs down. My boat is a 2001 Nitro 901. I am running a 23p tempest plus prop. The list of items above is what all I have did so far in a years time. 2 weekends ago is when I put the new cables and hot foot on. We thought that the cables may had stretched enough to not allow it to open up enough to take off. But that did not work. So I am at a loss. As is my mechanic.

[EuropeanAM]

Please provide your engine serial number.

Did this engine/boat combination perform properly for YOU in the past?

[JOE54]

^^^^^^^ +1 and has tuner ever been checked and verified

[Hunt2Fish]

I'll have to get the serial # when I get home this evening. When I first got the boat, I was told that it does what it is doing now sometimes. I am the second owner. The guy I got it from bought it new in 2001. The motor has less than 200 hrs on it. He used it as a crappie boat. So it was putted around. Before it started having issues regularly, I could make it go. Any time it would mess up, I could quickly pull back on the throttle and then go forward, and then it would go just fine.

[EuropeanAM]

Have a pretty good idea of where we're heading on this- but need to make sure we identify the engine properly (hate to send you looking for a component that's not there).

[got2fish]

Have you tried removing the pvs plugs from the prop? If not, that could help with venting for takeoff.

[JOE54]

^^^^^ +1 will help

[Hunt2Fish]

Sorry, I've been gone...
Ok. Si I have the serial number. It is #OT273329

[EuropeanAM]

Based on all of the items that supposedly have been done with no improvement- I would recommend dropping the gearcase and checking to make sure the exhaust tuner is still securely fastened to the bottom of the adapter plate (nylock nuts used on them often melt away the nylock, resulting in loose nuts, missing nuts, and broken studs. I know... sounds like a bad movie.

[Hunt2Fish]

Thanks man. I will pull that down to look at it. Like I said, this had been a frustrating journey.

[JOE54]

^^^^^^^++++++#5 and #11