Hey
@Seadoo_Utopia_Guy
Welcome to the family! I am fairly new myself. Got my boat 2yrs ago, but it needed to be repaired for 11 months. Just got it back last week and I am taking it back for another round of lengthy repairs early this morning. Having a degree in engineering, been very fascinated with boats and doing as much as I can to learn about my boat, and other boats, as best as I can. I don't actually have your boat or too familiar with it, to be honest, but hopefully someone else can jump in and help you and I both.
Just to cover the basics, do you know the service history of the boat? To start, I would definitely check spark plugs. I typically replace mine every year, my plan at least, as they get fairly worn out after a season. And for the cost, they're pretty inexpensive and both quick and easy to replace. I would also go through and check all your fluids, make sure you have enough oil and that it looks appropriate.
Just to make sure, are you positive you have twin 155hp engines? I see your boat had the option for twin 215hp SC engines, which would be similar to my boat's setup. Some people are unsure and misidentify their engines on occasion if they are unfamiliar with them. I even find a lot of "official" boating review sites and videos constantly misidentifying the engines. But I ask because what you're describing, if it were my engines, would be the clutch in my supercharger being worn out and slipping. The start of that slipping mimics exactly what you're talking in that the clutch will slip, unable to spin the SC and produce boost resulting in power loss and RPM drop age, but when that RPM drops, it suddenly "catches" again and spins the SC back up and making power. One of the characteristics of this happening, and what I'm constantly watching out for, is for the needle on one of my tacos fluttering exactly as you mentioned. For me, if I had a worn clutch, I need to rebuild my supercharger fairly soon, otherwise I could have a failure. More alarming is that with your model, if it is SC, there were issues with the components in the clutch assembly. Originally they were ceramic so that when they failed, they failed catastrophically and destroyed themselves and the engine. Over the years, they've improved and changed the material choices so that, for mine, the now metal washers would warp and flex and create that slipping feel, alerting me that it needs to be rebuilt soon and won't suffer any engine damage.
If you are certain you have twin 155hp, then ignore my latter message. Otherwise, if you are unsure or want to double check, you could attach a picture and I would be glad to verify it for you. Just to help out, I will attach a picture of what my engines are to compare too.
Hopefully I could have helped, sorry I was more rambling than informative, but figured you may appreciate learning a few things.
