Looking at a 1990 Evinrude XP 150 V 6 engine.
Anybody have experience with them?
Anything to be scared of?

"VRO" Motor. Oil pumps are known to go out for no reason and leave you with a couple of scored cylinders if you are lucky. If the engine is a good deal and passes inspection, bypass the VRO pump and run 50:1 mixed gas. You will guarantee oiling then.

...I ran a few of these in my OMC days before OMC went under, and I've worked on a bunch more. Check the manual as many of these require premium fuel or bad things will happen. VROs were always an issue until they got the bugs out. My 1984 had 2 pumps replaced, my 1989 and 1992 were fine. If the carbs get dirty the motor will run as if its on the chokes, and there's a lot of carbs to clean. If it's running on all 6 cylinders the ignition is OK. If not, I wouldn't touch the motor since its a real pain to trace ignition problems on these engines as they often only act up after a high speed run when they start breaking down under load. You haven't lived until you have to hang over a powerhead at full speed while using a timing light to check for which cylinder is missing under load- while your wife/kid/buddy is driving your rig. Last issue is a weird little shorting switch in the shift linkage that kills 3 cylinders when you shift. These fail once in a while and drive you crazy changing expensive parts till you realize its the darned $20 switch. A lot of guys have removed these switches over the years and the motor will shift into gear with a pretty good clunk. After a few years of this the lower unit gears and shifter digs will go bad and it will pop out of gear at idle. Absolutely run it on a boat before you buy it- or get a guarantee of some type.
Doug

as far as the VRO system, there is a lot of misinfomation about it. Like guys who say they have a cylinder or 2 that got scored from it. The system feeds all of the carbs at once with the fuel oil mixture, so if you have a problem with oil getting to a single cylinder then your problem is elsewhere.

take a few minutes to read this article on the VRO systems. Not saying the other responders to your question are wrong, just trying to provide complete information on this as this article covers it very well.

http://continuouswave.com/whaler/reference/VRO.html

PJ:

Thanks for the article reference. I've been running a VRO-equipped 120 horse V4 since 1991. I see I should replace the pulse limiter with the newer blue version.

I once saw what entraining air in the fuel does to motor behavior- smoke, spitting at idle and oily plugs, just as the article says. I traced it to a broken fuel line clamp on the suction side of the VRO pump. The clamp looked perfectly good, but when I wiggled it, found it had broken on the side opposite the rachet. When I replaced that bad clamp, the improvement was immediate and obvious. That's the only fuel/oil problem I've had with that motor in 17 seasons

The VRO system has worked very well for me.

yea its interesting thats for sure.

I printed it out and put it in my service manual