RPMs keep slowly dropping. And bogging Down.

[calebt23]

2016 250 mercury pro xs. S#2B360376

Only 50 hours on it. On a 2017 nitro z21. When I’m running it will stall at 5000RPM and start to bog down. I have to let off hot foot completely then Punch it to get them to shoot back up and hold there. Sometimes punching it as many as 8 times to get it to break free and get RPMS up. Also having low voltage alarms sound by end of tournament days. When the battery gets low enough I cant even get on pad. Replaced my cranking battery with brand new west marine AGM and still having issues by end of day. Could this be a bad alternator or bad sensor? I’m very lost on this issue. HELP!

[Savage]

Get the battery load tested.....Low voltage alarm=Performance problems.

[calebt23]

Thanks for the response.

I will load test but hard to believe the brand new battery I just bought was bad only 1 day after install. I was dead on the water and my buddy ran me the new battery on the water, installed and fired right up and ran really well back in and on the first run next morning. By end of the day was having same issues.

[Savage]

If the battery doesn't last ALL day, then something is wrong with it, or it is not properly sized!

[Cajunhunter67]

Check the Battery voltage while its idling (Volt meter at the cranking battery). Than turn on all your equipment you normally run. Make sure voltage is being maintained well above 12 volts.
I would bet the Alternator is not carrying the load.
You can also leave it on the trailer. Back it in the water. (Will need two people for this if you have a hotfoot) Run up the RPM's, make sure the internal regulator is not kicking the alternator offline as the RPM's rise.

[calebt23]

will give this a go soon. Thanks