New (to me) boat / need to rebuild engine
 

Just checked the oil and it's atleast a quart lower then when I ran the boat for less then an hour yesterday. Did a compression test and all cylinders are between 130-138PSI EXCEPT #8 at 62PSI. I also just tried to start it and magically no water would flow through the exhaust! Any advise would be appreciated.
James

water can take some time on hoses to flow out...not too long though! I suppose you have a 454 or 502. compression should be more in the 150 to 180 range, mostly equal, but certainly not one at 62. this one is burning oil for sure... unless you have a valve problem but you say burning oil so... I'd get a leak down test done to make sure you know what the problem is. I had many 454 MPI rebuilt completly for 3k, bottom to top... Hope this helps but let us know!

This engine is a 500efi with 164 hours on the computer.

compression
 

squrit a shot of oil into #8,and do another compression test on that cylinder.if the pressure increases,the rings most likely are the problem.if pressure stays the same,then you have other issues.hope this helps

The first thing I would do as mentioned above is a leak down test.

One quart in an hour that is alot of oil. Even if a valve oil seal is gone or the rings are bad that is lot of oil to burn.