Nissan 4-stroke NSF 6A2 6hp water in engine oil

[jjjewett]

I have a Nissan NSF 6A2 6hp 4 stroke that has a problem.
The engine oil gets milky after running it in water for a few minutes. I change the oil and it turns milky again after a few minutes running in the water.
I have purchased the service manual but it is not very helpful for diagnosing this issue.

I have been advised it might be the head gasket or the main seal?

I have ordered a powerhead gasket set (PN 3R1-87121-0) but Im not sure exactly what gaskets come in that set and if I should just replace them all.

What diagnostic test could I run to help determine what my problem is?
Is there any other seals/gaskets I should be looking at?

thanks so much!
-John

 

[pvanv]

Re: Nissan 4-stroke NSF 6A2 6hp water in engine oil

John,

If you are getting cooling water intrusion into the crankcase, you either have a leaking gasket of a cracked casting. This could have been caused by a severe overheat.

The 3R1871210M POWER HEAD GASKET SET 4A/5A/6A includes:

3H6010051M GASKET, CYLINDER HEAD
3H6023060M GASKET, EXHAUST PORT
3H6010240M GASKET, HEAD COVER
346010320M GASKET, THERMOSTAT
3R1074321M GASKET, BREATHER CAP
3H6074220M O-RING (2)
101001210M SEAL
3H6032930M O-RING, DRAIN SCREW
3H6020110M GASKET, CARBURETOR
3H6021040M O-RING, 2-33.5
334001220M OIL SEAL
3H6074020M GASKET, OIL PAN
3H6023050M GASKET, EXHAUST PLATE
3H6076050M O-RING, OIL PUMP
345660210M O-RING A
369012150M OIL SEAL (2)
369012140M GASKET
3H6610120M GASKET, DRIVE SHAFT HOUSING

Unfortunately, a leak-down test will only confirm whether you have a leak from the combustion chamber. In the end, a close inspection during disassembly should reveal the problem. In other words, at a minimum, you will be installing a new head or pan gasket.