There are 2 hoses on each engine plumbed from the valve covers to the flame arrester..No breathers or PCV..Just hose to arrester. I just installed 2 PCV's one on each valve cover on each engine..Since my carbs no longer had a large vacuum port, I had to install a 1" aluminum spacer with a 1/4" port under the carb.
Everything I've read about pcv's seems that they also remove moisture.. so i'll know within a month or so if that cured my problem...

Cam timing. One engine may be a couple degrees different than the other. If reversion is close, this can be the difference. BTDT.

If it was reversion... Wouldn't I see some kind of stain inside pipe or exhaust manifolds.See pics on other post..
Correct me if i'm wrong ..........
Reversion is water being sucked back into the exhaust portion of the riser pipe at engine idle speeds and after running at high rpms then pulling back on the throttle to idle position with large duration + overlap camshafts. . Then what happens to that water?? Turns to steam ?? How would that steam get into the valve covers and cause the oil to turn milky?? wouldn't wash the plugs clean ?? passes the rings and ends up into the pan?? Wouldn't it eventually buildup and show in the pan oil ??

Can someone clarify this

Just got off the phone with Eddie Marine tech support...

He says its not reversion...Not with the 114 lope seperation and 236 degree duration cam on my engines.. He did say put the pcv's back on

If you are on the edge of reversion pcv valves are a good fix. If you have reversion looking up the pipe you would see efforvecence (sp?) white spots after all is dry. If it is pure black carbon looking you have no reversion.

Slight reversion really just humidfies the crankcase after shutdown. As the engine decelerates to a stop the reversion increases. Then it sits there closed up and heat rises to the valve covers and condenses like an aquarium. Another helpful thing with slight reversion is to remove your oil fill caps/breathers at the end of the weekend. It allows the moisture to excape during the week.

why would running pcv valves going to the flame arrestor vs just running hoses to the flame arrestor have any benefit to removing condensation??

Ihad the same exact problem last seaon on both my 500hps, but my oil temp never gets above 190 even hard running, so i assum it is condensation,, where is the oil tstats on 500hp carb motors.

If it were me I would ditch the silent choice and get the long risers. Just my .02 cents, I know a lot about this stuff because I broke a lot of parts. Cheaper to set it up right than get towed in and be out of boating for the summer. I would not run the short risers and silent choice on anything other than a completly stock engine.

The pcv connects from one valve cover to the intake manifold or spacer under the carb..not to the flame arrester

Pressure test the water system on the engine. I Had the problem of an intake gasket leaking water into the oil galley very slowly one time. If it does not hold pressure you definitly have a leak somewhere. Also oil coolers and parts like that could do it too.