Can't get all the oil out of my M35 engine

[eisjeff]

I change the oil regularly on my 1996 M35 Universal but can't seem to get all the oil out when I change it. I can get 2.5 - 3 quarts out regardless of whether the boat is on the hard or in the water yet the engine should hold 4-5 quarts according to the manual. I have taken the oil out from the hose on the bottom of the oil pan and tried sucking it out of the dipstick and still when I put new oil in it is jet black as if I didn't change it.

My mechanic says that yeo this is a problem with this engine but has no answer.

[KWKloeber]

Are you accounting for the oil filter?

Apologies, I don't know -- where is the hose banjo located on "your" 35?  I know that some Universals are located mid-oil-pan and some are aft on the pan. 
I don't have a hose on my M25, but I use the dipstick and the stiff poly tubing (attached to vinyl tubing to the pump) and can reach both back corners of the pan.  The stiff tubing has a curve "set" to it that can be used to get to the back.

When you say jet black - immediately upon refilling?  Or after running? (diesels don't run "clean" oil like a gasser.)

-ken

[Jim Hardesty]

I can get 2.5 - 3 quarts out

How much oil does it take to refill?  If it takes near 4 quarts you're good.  I drain the oil with the drain hose using an oil extractor.  Makes for a very neat and clean job.  Refill takes 4 quarts.  If you are draining the oil with the drain hose using gravity may not work as well.
   
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Jim

[Ron Hill]

esji : Like Ken says it all depends where you oil drain is on the oil pan - mid pan like most Universals (Oshkosh) or in the rear of the oil pan (Westerbeke). 
The engine is installed on an incline so if the oil drain is NOT in the rear of the oil pan there is no way that you can ever get out all the old oil!!

A thought   

[Roc]

Before you change the oil, do you run the engine to bring it up to temperature?  I would think doing it on a cold engine, the oil is more viscous and harder to get out.

[eisjeff]

Thanks to all. Yes i run the engine. My oil plug is in the middle of the oil pan. I do understand that the engine in mounted on an angle. Still when changing the oil I would hope to at least have clean oil show on the dipstick after it is changed and before I run the engine

[Ron Hill]

eis : If your oil is extracted from the middle of the pan - The only time you'll see clean oil on the dipstick is immediately after changing oil!!  A soon as you run the engine (if only for a minute !!) you'll have dirty oil on the dipstick!!   

A thought