Not sure if this is the right place to post this
Im looking at a 2003 vintage boat with a 575sci and merc ITS/xr. motor has 13X hours on it. i have done my digging on the 575 and it seems the main weak links are the head gaskets followed by the blowers, with the TBI being next in line. at 13X if i don't run it hard all season " should" it last until a winter re fresh? is they any warning sighs to check for saying they are going to let go? i know on a car you can test the coolant for hydrocarbons. i cant see this being done on a boat with raw water cooling. with MEFI3 can you pull its running hours like on the new ones to see how its been treated? for the ITS are they full hydraulic - transom to helm or was it left to customers choice? if its not, how can i tell how far the hydraulics go? i know enough just to be dangerous haha is their anything to look or watch for on the ITS or any hydraulic steering system? do they have a rebuild interval?

any and all info or help would be greatly appreciated

The mefi 3 doesn;t have run history just total hrs,a leak test sea trial and general inspection is a good start,we have found with general hp use at around 300-400hrs a engine freshen would be nice,the old style head gaskets are usually the first thing to fail

Let me save you the trouble of worrying about the factory motor and show you where you'll be in a few years anyways, like the rest of us. Lol

You neglected to mention the weakest link ...XR.... You'll have issues with them before the head gaskets become an issue

crap. haha its a smaller boat its a 25 footer with a single step. i know ill have to be easy out of the hole. its currently got a 4 blade 28p. still going to be "the" weak link?

haha looks great ive already been looking at the pricing out a large whipple and MPI set up for "rebuild" time

Keep it under 3500 rpm and you'll be fine

that where the boost comes in?

Head gasket concerns are for pre-2003 575sci. They went to a better gasket starting in 03, according to previous threads here on OSO.

Blowers seemed to be fine until 200 hours or so. Many lived longer if spun at stock speeds. DMPE rebuilds/upgrades those blowers, best to do before the sealed bearings at rear of rotors fail causing catastrophic damage.

Boost will come in when the motor is under load. For example getting the boat on plane, accelerating your boat's speed while on plane, and/or above a certain rpm around (4000rpm) with mine I believe. Virtually impossible to avoid boost in a supercharged boat under normal operating conditions. I think you'll enjoy this setup just understand it won't be cheap to maintain. I've seen many owners of this setup on this website upgrade the blower with great results and IMCO has some nice drive upgrades that should bolt on to the current ITS setup the boat already has. It cost $ to go fast but it sure is fun. Buy the boat, run it for the season and save some money for winter upgrades as needed. Enjoy!

Dont forget the obsolete fuel injectors!