All you care about is the min and max when you 'get on it.' How you go about it is a moot point. Hopwever, the faster you get to the min is better so you don't have to wait long periods to be able to drop the hammer.

Everyone has different opnions on oil temp min and max's.
Mine is 180 min - max 240 maybe spike of 250 conventional.
180 min - 270 max synthetic. (We are not talking 5w-30 here). 270 is absolute max and I still would not want over 250F.

I prefer 15/50 /// 20W/50 .....Therefore not sure on lighter weight oils......which I pers do not want in my marine engines.

I hear you on keeping the oil in range.
I'm just wondering if it's a negative if your ceiling on the range is around 200 with a 180 oil stat as opposed to a 225 to 240 ceiling with a higher temp oil stat.

I don't anticipate a problem keeping the oil cool with a log cooler and in Lake Erie. I'm concerned about getting heat in the oil, thus the oil bypass stat.

I ran the permacool oil thermostats last season on my newly built motors. They fully open at 180*. At full romp the hottest I saw my oil was 200*. When I drained oil this past weekend I didn't see any moisture symptoms. in the oil. This season I'm switching to the Merc head mount oil filter with tstat, the square one. I believe these open at a higher temp so I'm curious to see how i run now. I use Mobil 1 15w50 from wally world

I mostly go on pretty long trips, therefore the 180-200 is fine for me. Plenty of time time to burn condensation out. I'd be fine with the 215-240 too though.

Now, many around me go on much shorter trips. Like, say, 1-3 miles...and sit for a lot, than come back. In that instance, especially considering our cold spring and fall water temps, I'd 1 million % go for the higher one.

In my small lonely world, lol, I see more engine's with oil contamination from short cold water trips than I do people baking their oil. In fact, I don't see anyone around here with a too hot of an oil temp oil breakdown issue...in boats.

I'm in the North on a medium sized lake. Just 21 miles long. Your mileage and use may vary.

Good point SB.
I suppose it's all in how you use the engine.

Thanks guys.

Well, I guess I haven't said much up until now---that "galvanized warsh tub" that I have been referring to the past 5 years or so....is really a 40' Hustler. It's the old 1995 race boat made out of Kevlar that won the "Worlds" in its class (or whatever you call it down in Key West back in the day). I wasn't sure if I was going to finish the boat or not so, that is why I have been kinda quiet about it here.

I wanted a piece of history so, I bought it back in 2010 or so. We completely stripped the boat from cockpit/dash to the stern/transom...everything---and now I can tell you that it is, for the most part at this time, starting to go back in the opposite direction. The boat is currently in an airport hanger here locally and has been a ton of work...a major restoration project to say the least.

Dave W has my blocks all cleaned and prepped for assembly and are on the stands now....cranks, rods/pistons have been installed. So, everything is flowing along in the assembly stage...boat, engines, and even had the Manning trailer completely restored/rebuilt last year at the Manning factory.

I remember seeing it up at Daves shop a few years back. I cant wait to see it done!

Very interesting read: http://hondakarma.com/data/attachmen...ing_System.pdf

One page (#55) shown I've included just below:
clearer if click this link: http://i59.tinypic.com/2cegpg.jpg
Remember:
80°C= 176°F
100°C=212°F
130°C = 266°F

If you go by that your engine will sludge and blow.