2001 Sportster LX Fuel in Oil.

[bigwig48]

This is a newly purchased used 2001 Sportster LX for my family.  The engine fires right away, idles smooth and revs-up with no sputter.  However, after de-winterizing this week, the oil was FULL of gas.  No viscosity left in the oil, like water.  Possible causes after researching:  fuel pump pressure too high (possible wrong pump), leaking diaphragm in mechanical fuel pump (this boat has an electric pump), Holley carburetor stuck open dumping fuel through the cylinders, or poor venting.  Any thoughts on what could be the cause of the fuel in the oil?   And please do not say bad piston rings.  What is the right part number for the Indmar 310 V8 electric fuel pump?  

[kerpluxal]

1 hour ago, bigwig48 said:

Holley carburetor stuck open dumping fuel through the cylinders, or poor venting. 

This is a common problem with Holley marine carburetors.. Highly likely, but would also result in flooding and the smell of gas. However, if you did not experience flooding issues or the smell of gas then this could be easily deducted as not your cause.

Your best case scenario would be to diagnose all until the problem is solved... 

Do you change your oil before storing? Highly recommend you do as you want the impurities out while the boat is not being used.

Before you winterized, did you check oil levels on outings. If no, add this to your checklist as well. If yes, did it have fuel smell then or seemed thin? Need to determine when the fuel got in to oil and that would help diagnose as well.. i.e. I checked my oil on every outing, it never had a gas smell nor was thin, so this would mean it is happening when you stored boat. Or, I did not check my oil, I don't know if the issue was pre-existing.

Have done a compression check on the engine. If not, I highly suggest this as well (not stating its piston rings, stating I would no matter what, especially on a used boat).

Edited May 16, 2019 by kerpluxal