This should be a discussion of "reasonable engine operation" techniques, especially in cool or cold water operation scenarios. Would especially like some input from others with extensive engine building experience:
There's been a lot of discussion regarding "engine temperatures" and "cold water operation" lately. One item is often neglected in these discussions: Engine shutdown!
In "non-bassboat" applications (let's just say general pleasure boats), the boat operator would, under most circumstances, be dropping to idle speed for at least a short period after a long run. No wake zones, docking the boat, trailering the boat, etc. will all require some period of engine idle.
Hence, we don't discuss the need for an engine's temperature to "stabilize" after a hard run in cool or cold water- it's usually a "given" for MOST applications.
However... in a bass application- it's a different story. Sometimes, the temptation to "fly in" to a spot at 75%-100% throttle, yank back to neutral and immediately shut down is overwhelming... especially when you just know that today's "big bass" is right there... waiting for you!
At high RPM's... the poppet valve in ALL of our motors is controlling the flow of coolant. Flow is essentially "WIDE OPEN". Those of you running Smartcraft can attest to this... you see temps of 120+ at idle... and perhaps as low as mid-80's at WOT. Combustion chamber (internal) temps, however, are "screaming high" on a really hard run... and it's just common sense that you'd allow the engine to idle for at least 45-60 seconds before shutdown. This allows the temps to "stabilize"... especially before you trim the engine up in a cove, draining 50% or more of the coolant from the engine, and allowing it to "perk" while you fish....
In all honesty... we put these engines through worse "thermal conditions" than many competition racers would! Long WOT runs, hard turns, low cooling temps (so far we're similar to racing....), and WHAM- turn the key off, trim the engine up, drain most of the coolant, and just let it sit there and PERK! OH... and we might be inclined to just fire it right back up a couple minutes later, trim it down, and before the cooling system has a chance to refill the block- go right back to WOT again!
Then we wonder why we see "thermal events" in the lower (or upper) cyl's.......
My recommendation: Don't just wait for the engine to warm up on cold starts- ALLOW TEMPS A CHANCE TO STABILIZE after a hard run- at LEAST 45-60 seconds before shutting down!
This post is NOT directed at anyone in particular- it's meant to be INFORMATIVE- something that many might "glean information from". Tech's- engine builders- owner's alike... let's hear your thoughts! (You've now heard mine)