New oil | Color difference already

[MaddyDean]

Hi All

I changed the oil two weeks ago on the twins.

• Port engine oil still looks new
• SB engine oil--still looks new(ish) but it is noticeably darker in color and also looks like there is particulate (very tiny darker spots)

Oil filters were changed and exactly 4 quarts of oil was taken out of each engine plus what was in the filters.

The levels has remained the same on both engines after about 2 hours on the engines.

is there a particular cause for this color difference?

I am thinking possible sediment in the pan. Also thinking to suck the oil out again and since I can get to the drain on the bottom of the pan (It is a pain but I can get there) i will drain any remaining oil. Also thinking of dropping the pan to clean out but that would really be difficult but I believe doable.

Lastly, full disclosure, after the engines sit for a few days (I try to start the engines every two to three days) there is a very quick puff of blackish smoke from the SB engine but, as mentioned, it is very quick small puff--like Bill Clinton.

thoughts.

 

[Dick Whetstone]

From the year of your boat (1991) I assume your engines have carburetors. Given the SB engine puffs black smoke on start up and given its oil is darker and / or has particulate matter in it, could the carb on the SB engine be running too rich?

Of course there are MANY other reasons, but check the simple stuff first.

 

[skolbe]

Running rich can cause this. My dock neighbor had been running very rich for 2 years and then decided to spray carb cleaner into his engines. Large sheets of Black Carbon were floating in the marina for hours. While the dock neighbors boat looked great and he changed the oil/transmissions annually - that much carbon can't be good - this is why an engine survey makes sense when buying even a "well" maintained boat.

 

[Alex F]

Based on what I've seen it doesn't matter whether the engine has carburator or fuel injection system. Some engines just run "dirtier" than others. I've had the same situation with my 320DA in 2007. As soon as I changed the oil, on the engines with only 268hrs that ran perfectly, the oil would be dark almost right away. 4 years and almost 300hrs later that boat still ran like new.

The biggest reason I was told that it's just not possible to get the old oil out completelly, there are always some pockets that will hold small amount of old oil.
I've heard stories that MM had customers complaints that they have been charged for an oild change while they saw that the "new" oil was the same color as the old one.

The bottom line is, if you know 100% that the oil and filter was changed and the engine runs fine, just go boating.

 

[skolbe]

I agree that the oil does get dirty quickly, within 5 to 10 hours it is fairly dirty.

 

[Gunn]

I probably wouldn't worry about it, but you may want to save some of the oil and send it in for an oil analysis. This place is pretty reasonable and I've had friends use them before with nice results: http://www.blackstone-labs.com/