I always use a strait 40 or 50 weight. That might bring up the oil pressure a little at idle.
BTW, you probably want to get the oil a little over 200 degrees to get the moisture out of it. Maybe add an oil thermostat?
Gary

I run Royal Purple straight 40,,,, have run it since 97. I still pull it after 20-25 hours though,,, it loos like new, but I just feel better. I agree with Gary also,,, moisture is supposed to come out of synthetic better, and Royal Purple claims that, but I would like t o see you temp a tad higher.

I agree with what Gary said. Run a straight 40 or 50 weight oil. I personally believe you need a happy medium between pressure and volume. You can have high pressure but when running hard you need to make sure you never run out of oil. Make sure you have good oil controls in place such as scrapers and windage trays etc. to keep oil in the pan.

Remember that a boat motor sees the same load as a car engine going up a 30 degree grade in low gear.

Also 180 oil temp is to low to burn off moisture.

Just want to say thanks again for the help. i do have windage trays in to control oil and running 10qt deep sump pans as well! i will get the 40 wt royal purple and try it. did a pretty hard run yesterday at 4000-5000 for a period and pressure stayed at 38-40. came off plane and had 20 at 800rpm but 30+ at 1000 and after the idle zone, pressure had ruturned to 45 at 1000! i think its ok or i would have seen something by now!

Russ call me.Heading down to FLA tommorrow.Cell number is 678-522-4873.Home 770-920-1444
Mark

I am having the same problem. using kendal 20 50, 50lbs cold and after a run 15lbs at idle, 20 at 1000rpm, Kendal has changed corlor, used to be green now clear. We compared it to penzoil 2050 , penzoil twice as thick, something must be going on with the oil,oil pressure was fine until last oil change with new kendal. When you pour it out its as thin as water,right from the bottle.