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496mag HO “very sluggish power” ????
Posted: Sat Oct 21, 2023 3:10 pm
by 282Captain
Here at year end, running the boat prior to winterization, my port 496mag HO is drastically under performing and very sluggish. Half power. More throttle does not produce more power. It’s extremely “fat” or sluggish starting off trying to get on plane.
Thoughts???
Re: 496mag HO “very sluggish power” ????
Posted: Sun Oct 22, 2023 9:01 pm
by MNStCroix
Bad gas? Years ago I accidentally put some in that had ethanol blended in and my engine ran sluggish like you described. Had to get it pumped dry.
Re: 496mag HO “very sluggish power” ????
Posted: Mon Oct 23, 2023 12:49 am
by bruceb58
MNStCroix wrote: Sun Oct 22, 2023 9:01 pm
Bad gas? Years ago I accidentally put some in that had ethanol blended in and my engine ran sluggish like you described. Had to get it pumped dry.
He has twins so bad gas should affect both engines equally.
Re: 496mag HO “very sluggish power” ????
Posted: Mon Oct 23, 2023 7:11 am
by Whippled263
What year in the engine? There is a Merc bulletin in regards to cool fuel system. Look it up and read about it. Basically the paint from inside the module delaminates and clogs the fuel injectors. This happened to my Powerquest with a 2005 496 mag. I had the exact same symtoms.
Re: 496mag HO “very sluggish power” ????
Posted: Mon Oct 23, 2023 7:09 pm
by bruceb58
Whippled263 wrote: Mon Oct 23, 2023 7:11 am
What year in the engine? There is a Merc bulletin in regards to cool fuel system. Look it up and read about it. Basically the paint from inside the module delaminates and clogs the fuel injectors. This happened to my Powerquest with a 2005 496 mag. I had the exact same symtoms.
On the same line of thinking, a fuel pressure check should be performed.