WHAT happens to a boat sitting in water for TWO years?

Raw water pump impellers on all.

Gas or diesel? What brand engines and gen

Some gas gens don’t like to sit…

Indeed sitting for 2+years is never good. A monthly start up helps as long as the engines are brought to temp and briefly put in gear. Having had a recent oil change means you can’t do an oil analysis…

seller need to address the overheating and gen issue but at this time you re already out the survey and yard costs. This is why one should always do a sea trial before survey to make sure they are no major issues, especially with a boat that’s been sitting

The OP mentioned a monthly start.
While this of course can't stop the marine growth on intakes and heat exchangers that DM suggested, I would expect it at least to be enough to keep impellers in decent shape.
Not saying they are OK (who could?!), but I'd rather check possible raw water restrictions first.

No telling how old the impellers were before the boat was stored.

Monthly starts. On the fence about this.
Never up to temp and if just warmed, a condensation magnet.
It does move some oil and works the valves.

This model boat came with LBCs or Cummins 6s.

Send us the web address for this sale, This may give us more details than asking you lots of questions.
Was the gen-set run under load (ACs, water heater, stove-oven) for a while?
There are a lot of Carvers out there.
IMO; Carver boats had lots of style to catch shoppers eyes but not the best boat out there.
Your looking at a 21+ year old Carver. Suspect everything.
700 hours on 21+ year old engines?
That could be another birds nest.
Maybe gas replacements. Birds nest just got larger.

If you are planning on da big loop. Pick up some guides and study distance between fuel pumps.
This may help determine your range, speed, vessel fuel (water) capacity and engine (fuel) type.
With these notes in mind, Twin big gas engines and small fuel tanks may eliminate some models while shopping.

Also in the loopers guides are notes on vertical clearances. Some bridges are low and fixed.

I've never done the big loop. but we have traveled. 1350 gallons of diesel has looked thin a couple of times.

I'm also not a fan of monthly runs at idle, in spite of the fact that it's a very popular approach around here.
When during winter I'm not moving my boat possibly for 4 or 5 months in a row, I prefer to just rotate them manually by 190 degrees every 3 or 4 weeks, but without cranking them.
If nothing else, this moves the impellers, and any open valve is closed.

My previous comment was not meant to support monthly runs in general, just that at least it's good for the impellers - which could still be bad anyway, of course!

Yup, I suppose that "a 370hp diesel" was a typo.
But didn't they use Cummins rather than VPs?

Carver had their deal of the weeks on gas power. Mostly VP & Merc LBCs. Once we worked on a Carver/Crusader LBC install.
WorsterBreaks, Oh-No and Kohler on the gas gen-sets.
Diesel, Mostly Cummin's 6s and Oh-No D gen-sets.

The Cummins are pretty bulletproof, at 370hp they must must be C series 6CTAs unless by 2001 they were electronic, not sure when that started. 370hp is pretty conservative for these engines and easier to maintain and get parts than Volvos.

The 370 was near the last of the mechanical (Bosch - HO) 5.9L Cummins. There was a few more higher HP versions but the engine life was reduced and those models were short lived.
Then the slightly larger displacement C series started coming available.
You can only extract only so much dependable HP from so much Displacement (3208 owners still have issues here).
Parts are certainly still available. Correct parts WITH serial number in hand.
Attached is a note from my salvaged files.

I still question a 21 year old boat with 700 hours.
If original (really?) flags do arise quickly.
Ya know the original air charge coolers (alloy) are toast. Could be the overheating issue. If so, about 10$K per engine for new.