My 1988 First 285 has a VP 2002 18hp diesel. The boat your looking at may have a VP 2003, this is the 3 cylinder version of the 2000 series. I have had my boat for about 5 years. It doesn't have an hour meter.
My engine has been 100% reliable with one very small exception, when I bought it the tach didn't work because the factory engine mounted multi-fuse was bad. The previous owner wired a secondary start switch, the motor started fine but the tach didn't work. I traced the problem back to the multi-fuse, the first 2 positions looked fine but a meter proved otherwise. After I switched to the 3rd position everything worked. I change the oil & filters every year or so. I have replaced the belt and the impeller once. I also set the valve lash, only 1 needed a very slight adjustment.
The 2000 series does not have glow plugs but I have never had trouble starting mine if the proper cold start procedure is used. I have started it a 35 F.
The parts for a 2000 series VP can be very expensive and difficult to find. Example, the repair kit for the coolant pump is $310, the repair kit for the fuel pump is about $150 if you can find one. I hope to move up to bigger boat before I need parts!
Many people do not like the 2000 series VP engines. There are a few known issues, like the transmission input shaft on the older units like mine, but so far I've been lucky.
* Edit - OP you posted that it is a 2003 series while I was typing.