Oil coming from exhaust riser rubber coupling

[Ng321]

I was testing a new carburetor on the lake. Couldn't go over 2500 rpm WOT and definitely wouldn't plane. After 10 minutes the engine bay was full of blue smoke and oil was spraying out of the exhaust riser rubber coupling. Where do I start?

Extra details: engine timed, new spark plugs and fuel pump, runs really good at idle and about 17" of vaccum.

 

[alldodge]

What motor, and serial numbers are best?

This is a new problem, as in the motor could reach WOT before?
Check the oil and is it low now?
Any water in the oil, milk looking?

 

[Ng321]

The serial number looks like OD8104 but its very worn. 3.0L Mercruiser the engine would go over 1400 rpm before the new carburetor. The oil level is a bit high with no milky appearance just alittle dark. Im not sure if its a new problem the previous owner won't respond after he sold me this heap.

 

[alldodge]

The serial number looks like OD8104 but its very worn. 3.0L Mercruiser the engine would go over 1400 rpm before the new carburetor. The oil level is a bit high with no milky appearance just alittle dark. Im not sure if its a new problem the previous owner won't respond after he sold me this heap.

Sounds like there was an issue, and with oil coming out the exhaust, it either has a cracked head, piston or block

Do a compression test, but for the most part it does appear you will need to rebuild or replace

 

[Ng321]

Sounds like there was an issue, and with oil coming out the exhaust, it either has a cracked head, piston or block

Do a compression test, but for the most part it does appear you will need to rebuild or replace

SN shows 92-93 3.0

yes its a 1992 VIP. Compression is 165,165, 165, 170. I was hoping that at the worst I'd have to rebuild the top end

 

[Rick Stephens]

yes its a 1992 VIP. Compression is 165,165, 165, 170. I was hoping that at the worst I'd have to rebuild the top end

New motor won''t be that high without there being oil or water in the cylinders. What did the plugs look like?

 

[Ng321]

New motor won''t be that high without there being oil or water in the cylinders. What did the plugs look like?

They all were all black and #4 was wet not sure if its oil or gas, most likely oil