i have a 2000 fountain classic with 500 hp's ... ran it full throttle at 5200 rpm's...for a good 35-40 min non stop in the lake this afternoon... i noticed that the oil temp was at 230 degrees... i see the top of the gage shows 320 degrees ..... but it seems a little high...anyone with those same motors ever see this high oil temp ?

I do not know what you expect, but running it that hard for that long it does not supprise me the temp was that high. We once raced a whole race at 240-250 and with Mobil one we had no problems. Running regular oil might be a problem.

The HP500's in my old boat would run up to
220 after a good flogging.

As I recall, the oil cooler thermosats opened 210*,
to burn off condensation.

Normal for mine.

thanks fellows....i will add some high tech additive for race cars i use in my race car... it helps diminish the temprature a little as it leaves a coating on all metal parts, therefore less friction...
i'll let u know on my next run if it makes a difference.

That's some hard runnin'!! I use only Mobil 1, 15-50, and I haven't seen anything above about 205. Of course, I like to baby mine 95% of the time, and that 205 came only after some decent WOT time. What oil are you using?

I run in Galveston bay. In the winter with cooler bay waters my oil temps run much cooler. However, as the bay heats up in the summer it can reach 85+ degrees this is when I see higher oil temps bit never over 200. Also synthetic oil does seem to run cooler. With that being said, I never run that hard for that long!

How fast?

Check your oil coolers. Maybe not enough water flow.

I bet you had the cleanest valve cover undersides.