Suzuki DF140 Oil Change - Quick Question

[Westie]

Hi there,
I'm planning to change oil in my twins DF140s this afternoon and having a bit of a debate with my buddies. We hauled the boat out last weekend and its been on the trailer with the engines verticle. Should I start the engines to reduce viscosity prior to draining or just drain it cold? The working theory on the later is to prevent the oil from distributing thus allowing an easier and more complete drain.

The outside temp will be in the 70F range. Not sure if that would factor in here.

This will be my second change overall. Any additional advice is certainly welcome.

[potter water]

I do my outboards cold. The viscosity issue is there, but you just have to wait a while longer. And yes, the oil does pool up more in the crankcase after the engine is shut down and you do get more out. At least that is what my own experience has been. I'm pretty sure that the general wisdom is to run the motor up first though I don't see the reason for that.

Here is one experts opinion. It seems to me to counter his own argument about contaminants. If they are distributed, I'd rather have them collect at the bottom rather than stay distributed.

"Before you begin an oil change, the engine should be hot. Warm oil is easier to suck through a rubber hose or brass straw, but the reason for running the engine is more essential than that. You are changing the oil because it is contaminated with abrasive and chemical impurities. But the dirt in oil is just like dirt in water; leave it undisturbed and it settles to the bottom. Suck out the cold oil and much of the dirt stays behind, immediately contaminating the fresh oil and defeating the whole purpose of the oil change. Run the engine to get all of the contaminants in suspension so they come out with the oil."

[Sunbeam]

It sounds to me like the person who is recommending it be hot and any contaminants distributed, is going to be sucking the oil out. In other words, from above (maybe the boat is in the water, etc.). In that case I could see wanting them not all at the bottom where the sucker might not get them.

But in our case, presuming draining the oil out the drain plug by gravity, then I agree with you, why not have all the oil at the bottom. Just so happens I'm taking a lunch break mid-engine-maintenance (changing oil/filter and gear oil), and I'm doing them "cold," having let everything settle out. Mind you "cold" is still around 85ºF. But the oil seemed to drain out just fine. So I guess to me the best is all settled out plus warm weather.

[thataway]

I change when "warm". About a half an hour after shut down. Still warm enough to flow well, and most of the suspended particles have drained into the lower pan, but fairly well suspended.

Beside my favorite car guys, "Click" and "Clack" (From "Car Talk") recommend this method. Heck, a mechanic from MIT cannot be all bad!

[Westie]

Thanks for the feedback. I ended up doing it cold. Feels great to have changed gear oil, engine oil, oil filter, and fuel filters. Ready for another 100 hours!

[Pacificcoast101]

In case anyone needs a reminder about how to change their oil;
https://www.youtube.com/watch?v=WkDCpqgFkHs

[localboy]

I usually do as Dr Bob stated: warm and I give the engine time to sit and for the oil to settle down into the oil pan/sump.

[tsturm]

[BrentB]

I change the oil when boat is in water and fully warmed up using a Topsider portable pump and container. Very easy and clean.

I have a electric portable pump but use Topsider more