PDA

View Full Version : Help...oil leak in 2 stroke 25hp Nissan



LMBarnett
01-02-2009, 11:27 AM
I have an oil leak in my 25hp Nissan. Oil leaks out of a holeon the bottom of the L.U. after running (circled in red in pic below). I am not sure why it is doing this, does anybody have a clue?

rcfillingham
01-02-2009, 11:36 AM
That looks like your lower unit lube port. Make sure the rubber o-ring on the plug is intact and that the plug is tight. If not the lube port could it be a spline seal?

LMBarnett
01-02-2009, 11:42 AM
That looks like your lower unit lube port. Make sure the rubber o-ring on the plug is intact and that the plug is tight. If not the lube port could it be a spline seal?

its not the oil plug, that is on the other side. How do I check for a spline seal, and how expensive is that to fix?

rcfillingham
01-02-2009, 11:45 AM
Also called primary main drive shaft seal. Had one go out on my merc. Had it fixed ayt shop, about 200$., but that was a few years ago. Good luck

Barnacle Bill
01-02-2009, 11:49 AM
I've worked on a lot of outboards but never a Nissan. If that is an exhaust relief it could be normal if your motor is running a little rich.

Flatwater
01-02-2009, 02:10 PM
My yamaha always leaks. There are 2 pockets that are just there, you can see them when you change the water pump. For some reason oil collects in them and they weep. When dirt, mud stuff gets in the pockets they leak for a longer time. I run the motor rich on oil, 40 to 1 also.

Scrapper
01-02-2009, 10:33 PM
I agree, could be relief....looks as though exhaust comes out of it....unless it has been wiped before the picture. IMHO if your lower lube is not white and pasty, you have no water intrusion. I would leave it alone. If you do have water getting in...ie..white lube. Have a shop psi and vacuum test the lower unit. When they put psi on it...(normally 15psi)...they should submerge it...this is if it fails to hold the 15psi for normally around 30min. While submerged bubbles will come from the leaking seal. Check your lube before you do anything...if it checks out...forget about it. Be sure to replace the oring under the screw after you check it...many orings and washers will "seat" when they are tightened...when they are retightened they will not seat the same and a leak can occur. Many people do not realize this and think they have seals leaking when its just that oring....they take it in to have new seals put in and are out $$$. When it was just a 50cent washer or oring. Always look at the simple and cheap first. If you have a bicycle pump and can rig a gauge inline on it you can check it yourself in a bucket or tub. You'll have to rig up some sort of way to seal it...like the rubber end of a air blower on a compressor. I don't know if "air blower" is right...the thing you use to blow yourself off after working the shop...many of them have rubber on the end. you can push that into the drain hole and hold it...have someone pump the bicycle pump to 15psi. If it holds, and you had water in it..I would be its one of the drain seals. Just some stuff to check before you spend any money. good luck...let us know what you find out.