BUP,
I apologize for my poor reply posting. I respect your knowledge, appreciate your time and regret I didn't reply with more info. Let me try again. The boat does NOT have DTS. This is my first season with the boat. I noticed the problem about 2 months ago but I think the problem has been there all along. I replaced the original looking plugs with ac-41-983, cleaned the flame arrestors, the muffler and the cavity. The anti freeze was changed in 2014. I did not replace the t-stats, the engines warm up quickly.

How about fuel filters? Have those been serviced yet?

No apology needed was trying to help. Its always hard to pin point people boats going off a sentence or 2 or even a story book description of whats going on. I thought maybe the boat was new to you and like I said, I am not convinced 100 % that you have problem possible and I will add maybe a small one lurking that could increase to a bigger more noticeable problem. Time will tell.

How much throttle are you giving your engines at 110 degrees and below ?

One of the best things you can do is scan the engine and log at start up running and again as the motor is warming up. You can watch your temps of the engines to see if they match your gauge and any poor running conditions to what temps. Scan one engine at a time. After all scanning compare your parameters between the 2 engines and look for fault codes especially in the history. I would make copies of your scans and or download them to save. Once saved you can use them for reference compared to any engine scans down the road plus you can always send your scans to whomever to look at. .

Fuel filters, oil filters, engine and drive oils changed. I appreciate everyone's input and now understand the right way to solve this and any future problems is to scan the engines. I plan to get a scanner. I'm beginning to believe the hesitation is programmed to prevent any ramp up before some heat gets in the engines.

I agree and like I said all along in posting is - I am not convinced 100 % you even have problem - 110 degrees and below is still a very cold engine no matter what the app is.

Mercruiser has always made the claim engine(s) need to be fully warmed up before getting into the throttles especially nailing them getting on plane.

The hesitation comes with any movement to the throttles. I'm convinced the hesitation is programmed. Thanks.

Furthermore, all engines, transmissions, drivetrain, greasable bearings, and etc,etc tell you that too. :wink:

Annnnddddd - You forgot all about oil pressures and oil temps to SB

Exactly.
My 'etc,etc' covers all things I didn't type out. LOLllllllllllll.:bunnydance: