2008 4 Stroke 8 HP Nissan Leaking Oil

[Plandeck]

My 2008 4 stroke 8hp Nissan outboard has started leaking oil after an all night ride this summer. She has never leaked before. I discovered it dripping down the back of the lower unit. its clean amber oil. Not dark and full of carbon deposits. Have I blown the head gasket?

 

[pvanv]

You really should start a new thread; this one is almost a year old, and is about a different motor.

Check your crankcase level, and make sure the drain plug for the crankcase is well seated.

 

[GA_Boater]

Plandeck - Took the liberty of starting a new topic for you. Piggy backing onto old topics doesn't get you much help, especially when the old topic is for a different motor.

 

[Plandeck]

Ok...so I removed the power head and turning it upside down it seems pretty clear that the copious amounts of oil leaking down the back of the lower unit is coming from the oil pump! This I checked and both the O ring and the gasket look fine. The bolts and cover screws were tight. What should I do? Anything other than replace the O ring and gasket? Thanks.

 

[pvanv]

What o-ring? The pump is cam driven, and has but one gasket mating it to the head. The oil pump is serviced as a unit, so if the cap is leaking, you should get a new pump.
Was your oil level correct? Was the fill plug seated?

 

[Plandeck]

Thank you for the reply Paul...I did now replace the oil pump and gasket and the basement gasket...I did not replace the cylinder head gasket. Only the spring will tell if this solves the leak problem. Does the cylinder head gasket ever "blow" permitting oil to escape? I can't think of any other answer to the problem. Yes I've checked the oil level more than once...since there was never a problem before that overnight trip I don't think this is it. Regards,

 

[pvanv]

I would never re-use a metal head gasket on an MFS 8/9,8. You are inviting a problem. It would be possible to get either a coolant or oil leak, aside from the possibility of a compression leak.

 

[Plandeck]

you misunderstand me...the cylinder head has never been removed...I surmised that I might have "blown the head gasket" on the all night ride down lake Michigan which is when the oil leak began. (I pumped out the bilge in the morning leaving a bright oil rainbow around the boat) The question I put to you was, does a cylinder head gasket ever "blow" allowing copious amounts of oil to escape? Visual observation from outside the gasket seam revealed no problems. I did not remove the cylinder head and replace the gasket because I felt I was already pushing my luck removing the power head etc...Hope I got her back together right and she starts up in the spring!

 

[pvanv]

I've never personally had a head gasket blow on an MFS8/9.8. It would not hurt to check the torque on the head bolts.

 

[Sea Rider]

The only possible way to blow a head gasket will be due to a severe overheat, that's having both water intakes clogged with debris, plastic bags, you name it, not seeing the peeing indicator working as it should specially at night. A blown head gasket will make the engine miss throughout the throttle range, will find your plugs to be lightly rusty when removed.

Happy Boating

 

[Plandeck]

I think it is the engine basement gasket that is leaking...is this typical? would you recommend replacing the gasket and using a gasket sealant? Any recommendations?

 

[pvanv]

No sealer is needed.