Oil leak 2004 4 stroke nissan 18hp

[kburke]

Hello all,

I have a 2004 18 hp nissan 4 stroke that is leaking oil bad. I stored it over the winter like the manual said (with the tiller side down on the garage floor). When i picked the motor up to put on the boat yesterday oil started to pour out of a little hole on the bottom of the lower unit and out the prop. It is not lower unit oil but crankcase oil that leaked out and it was not the holes for the lower unit lube but a hole on the other side of the LU. What could this be? Like said before the motor was stored according to the manual. I also pulled the spark plugs and they were dry and not soaked with oil. Any help would be greatly appreciated.

Thanks, Keith

 

[pvanv]

Re: Oil leak 2004 4 stroke nissan 18hp

Keith,

Transport and storage of any 4-stroke can require extra care. If you raise the LU above the power head, even for a second, when hauling the motor on and off the boat, oil will run where it shouldn't. That can be into the cylinders, out the vent, etc. Also, if the crankcase was too full, the oil could run out even if the motor is laid down on the proper side. The best way to store the motor is upright -- on a motor stand, or even a home-built 2-by rack.

That hole you describe is likely a water drain, that allows water to get out of the exhaust areas rather than freezing in there. I suspect that you don't have a leak at all, but rather that the oil ran out when the motor was handled, and is now draining out of the exhaust housing.

I would check the level on the dipstick... make sure there is enough, but definitely not even a drop over the full mark. Maybe also pull the plugs and cycle the motor by hand (using the recoil starter -- but be in water so the water pump does not run dry) to clear any oil that might be in the cylinders. Then put the plugs back in and fire her up.

 

[kburke]

Re: Oil leak 2004 4 stroke nissan 18hp

I went ahead and drained the rest of the oil out and am going to put a new filter on. i am going to stop and pick up some 4stroke oil and refill the crank case and see if any leaks out while in the upright possition on the boat. If it still leaks i must have a bad gasket or somthing. I'll never store it on its side again! I did pull the plugs and they were dry and not soaked with oil. I hope that the problem was just how it was stored over the winter.

When i change that filter should i pour a little oil in it or is that not necessary?

 

[pvanv]

Re: Oil leak 2004 4 stroke nissan 18hp

You will likely be OK once you change the oil. Of course, expect the old oil to continue to be a little messy until it all drains off. Run only non-synthetic 10w-30 FC-W rated 4-stroke oil. Do not overfill -- not even a drop. Some will be needed to fill the filter. You can fill to the F mark, and then after running a couple of minutes, recheck the level and refill as needed. Yes, you can pre-prime the filter, but then getting it on the motor without spilling oil everywhere can be a problem. We usually prime the oil system by pulling the recoil starter (or cranking the electric starter) a few times without firing (with the stop lanyard off).

 

[kburke]

Re: Oil leak 2004 4 stroke nissan 18hp

I changed the oil and ran the motor. everything seems fine. Must have been how it was stored. Thanks for the help!