water mixing with oil during start up proceedure

[Solitaire]

During spring start up water mixing into oil. I'm aware of the need to turn off water intake while cranking over engine to start up. Yesterday on land with no water being pulled into exhaust engine started up nicely and we ran for about 30 seconds. Shut engine down, attached water intake from bucket (not directly from hose) and cranked engine over maybe 3 times for 5-8 seconds each time, engine didn't start. Checked oil and water had entered block emulsifying into a thick milky white texture. This same thing happened last year during spring start up but we thought because we had water running through system and cranked over to many times attempting to start. We flushed out oil as recommended by changing multiple times and with boat in the water started engine up and it ran well all season. At the end of last season we winterized including flushing fresh water through the system and again changed the oil.
Any thoughts as to why we are having this problem during spring start up on the hard?

[ndutton]

Knowing the boat is in the snow belt and needs winterizing, a cooling system pressure test is in order:

https://www.moyermarineforum.com/forums/showthread.php?t=11111

[Dave Neptune]

How "high" did you have the bucket set. If above the engine it could syphon in if allowed to sit long enough. If the oil NOW stays clear your block is probably OK but worth a pressure check.

Dave Neptune

[Solitaire]

Thanks for the comment regarding the height of the bucket. We position it clearly higher than the engine so it can drain into the galley sink if needed. A compression check is in order. I did locate an older thread that addressed possible causes for water in the oil, lots of rabbit holes to go down! Trying to start with the simplest diagnostics 1st. We've had this boat for many years operating with the same exhaust system and both winterized and commissioned it exactly the same way without this occurring. Only thing different is prior to start up last season I replaced an older heat exchanger with a new one and this spring replace the exhaust flange to the manifold that had started to throw off smoke. When we removed it, it was quite charred and starting to break down.