Just getting ready to buy a Quicksilver...

[RML_L]

Just getting ready to buy a Quicksilver oil removal pump that extracts used out through the dip stick.  What percentage of the oil will be removed?  I usually use some type of oil-clean product (Gunk Motor Flush) to clear out deposits and any accumulated sludge.  Use it on the automobile, but in that scenario you are able to completely drain the oil.  My boat engine has about 150 hours on it.  The oil is dirty, but not obscene.  Thoughts?

[wingless]

Those dipstick oil removal pumps are the common method for oil changes.

We share the same concern for the effectiveness of draining of the oil sump.

My over-the-top solution was instead to design and install a high volume / high capacity five-zone oil change system, one for each engine, each transmission and the generator.

Mine sucks out eight quarts in ten seconds, for a five minute oil change. Mine handles oil at operating temperature, so I change the oil after having fun w/ the boat for the day. Mine has bronze gears. If a pump w/ rubber and plastic is selected, then ensure that the temperature limits for those parts are not exceeded.

Mine is plumbed into the oil pan, by replacing the sump drain plug w/ a banjo bolt to the tubing, valves and pump.

Even if the dipstick method is used, an engine has many puddles of oil that don't fully drain into the sump, so even if the sump is fully drained, once the engine is started that old oil will contaminate the new. That is not a problem, because the fresh oil, w/ fresh additives and w/o contamination is the large majority, even if those old drops change the color from clear / golden to darker.

The best option is appropriate / frequent oil changes, at-least as often as specified by the manufacturer. Once an oil change system is on-hand then that is all possible.

Yes, the Gunk Motor Flush won't fully drain, so some of that "kerosene" will remain w/ the new / fresh oil and isn't a great choice. Frequent oil changes are better.

[wingless]

Here is my custom high-volume / high capacity five-zone oil change system.

[RML_L]

Wow, very impressive, and I am not easily impressed. Thank you for your helpfulness, as always.

[wingless]

Thanks very much.

Part of the high-speed is attain by using large inside diameter plumbing. All the hoses are 5/8" ID for my system.

[wingless]

The banjo bolt w/ fittings was used to replace the original drain plug.

The system was installed when the oil pan sump was full of dirty oil. I just removed the drain plug, obstructed flow w/ my finger until the banjo bolt was installed. Removed one of the hole plugs, obstructed flow, replaced w/ the next part. I did this until I was able to get the hose end above the sump level. The small amount of spillage was captured using newspaper sheets on the floor below the engine.

[RML_L]

Incredible engineering and knowledge of the anatomy and physiology of boats and motors and mechanical systems.