1 hour ago, MustGoFast said:

It shouldn't make much of a difference and I call BS on any impact to the cats, that said I'd consider the 25 if I didn't live in WI and never ran the boat on a cold morning

Thanks.. maybe it’s just brand specific with the synthetic additives they use?  
 

Here’s the article/ advertisement I came across…

 https://www.lucasoil.com/product/4-stroke-marine-engine-oil-sae-25w-40/#

2 hours ago, oldjeep said:

Let me ask this.  Does your engine temp run higher than the engine temp of someone in MN?  Or does your temp stay around 200-220?

Good point.

Perhaps then it’s more related to start up temps..? It’s 10:15 pm right now here in Arizona, and it’s still 97* outside, and around 110* during the day, so no cooling down.

Anyone weighed 2024 23LSV on a weighbridge versus what Malibu says they weigh

If so, when it was weighed what was in it regards fuel and gear, plus what was trailer weight

Malibu says approx 5700 lb, 2586 kg dry weight , but doesnt specify with what options etc

You may have a short to ground in the switched ignition circuit.  I had that happen on a similar model because the speedo paddlewheel harness rubbed on the transmission mount.  The extra movement and vibration of the powertrain when the boat was loaded heavy would make the mount rub on the damaged harness and blow the ignition fuse.

It shouldn't make much of a difference and I call BS on any impact to the cats, that said I'd consider the 25 if I didn't live in WI and never ran the boat on a cold morning