Oil pressure and temp gauge

Sounds electrical. Check fuses.

2 gauges with max indications is what leads me to a fuse. Often multiple gauges will be on a single fuse. After that they're gong down separate roads. If you have engine room gauges I suspect you'll find everything fine there, in fact you indicate that by the fact that it runs fine. If not a fuse I'd look for the leads to those two gauges shorting on each other.

Do you have Mans? The temp, oil and tranny gauges sometimes have a common ground. When that ground is interrupted the various gauges will pin when you energize the system depending how they were wired. The ground wire may be wrapped into and lead from the oil sending electric. May not be the problem, but its a start if you have Mans. Check for broken wires at the entry into the end connectors as a likely spot.

I assume you're talking about warmed engines for the temp gauge when you turn the key? Do you have another set of gauges in the engine room for that engine? How do they read?

I think that boat has CATS.

You could look up the boat and see that most were equipped with CATS or look on his profile and see that he has CATS.

It's a ground issue on the gauge circuit.

That's where my head went, but would hep to actually know the engine and setup. Note to boater: Murphy switches.

With 3208 cats, my guess is it's at the wiring harness plug. I just had to fix an issue there on a boat of similar age, pins in the harness connector were all in pretty poor shape, had to bypass one.

If it's an older mechanical engine, even easier for solving as you get to avoid the computers. I'd just jump a new direct wire from the sender to the gauge and rule out both the sender and the gauge. If the problem persists, shift that gauge to the other engine to see if the problem follows it. If not it's the sender.

But this is a bunch of guessing for a poster that didn't proffer enough data and didn't seem to stick around for the outcome of his request for help. I'd absolutely have a set of Murphy's on board, not relying on electrical gauges.

Good thought, but do the sensors go through the harness plug? These are 2002 3126b's. I'd search for a point of commonality which this could be IF they're run trough the harness, but otherwise (and first) check if they're on a common fuse or breaker or where the wires are first bundled near the helm. It could be as simple as a pop breaker popped or a fuse gone bad.

The 3208's I recently dealt with on a Black fin, the motor had a wiring harness, it had 1 plug with around 20 wires on it, then the wiring went from that plug throughout the boat or wherever it needed to. The fact the gauges are moving, tells me they're getting power of some sort, my guess is a grounding issue. Could be directly behind the gauges at the helm, or on the engine, or?