leak from my Evinrudes lower unit...

[jonboatbassin]

got back from fishin today and when i was unloadin the boat i noticed oil or somethin coming out of the left(opposite side as boats console) of the motor. it was down near the bottom coming from a small hole which had a screw next to it if i remember right and the opposite side had 2 screws close to where the others were. What could this be and is it a major problem?<br />The motor is a Evinrude 35hp 1979. If i remember correctly, the model# is 35953. I can get a pic of it tomorrow if need be but its dark now. Thanks in advance for the help guys.

 

[xp300]

Re: leak from my Evinrudes lower unit...

sounds like the driveshaft seal- or shift shaft seal.

 

[miloman]

Re: leak from my Evinrudes lower unit...

help us out jon what made it to happen did you hit an object

 

[OBJ]

Re: leak from my Evinrudes lower unit...

Johnboat...the hole it was coming from, is it round like it was put there? And what color was the fluid coming from the hole? If the fluid was dark to black, it's probably from the exhaust. The hole may be a cavity drain put there to drain any water from inside the lower unit so it don't freeze in the winter.

 

[ob]

Re: leak from my Evinrudes lower unit...

jonboatbassin,First thing I would inspect is the condition of the lower unit oil by draining and changing and note whether it is milky in color, ie indicative of water intrusion.If there is a leaking seal on the lower unit allowing gear oil to weep out ,it is also likely that water would leak in when motor is submerged in use.Non water laden gear oil will either appear caramel in color, if fresh, or dark brown to blackish if in need of change.

 

[OBJ]

Re: leak from my Evinrudes lower unit...

Up front darn good advice from ob.

 

[jonboatbassin]

Re: leak from my Evinrudes lower unit...

outboardjim- ya the hole its coming from is a round hole that i guess is meant to be there. the liquid is a very dark brown to black color and smells like oil(to me atleast). i noticed it hasnt leaked anymore since i noticed it about this time yesterday... with this info would you think it was jut exhaust still?<br /><br />OB-could you give some instructions on the fluid change? this is my first outboard, other than my little johnson4, and yesteray was only my second time out with it so im still fairly new to everything. so do you agree with what objim said about teh exhaust or could it be something more serious.<br />BTW- yesterday i did run it a little rich( probably about 40-45:1 (if the bottle was right anyways) if this could be any cause of it.

 

[ob]

Re: leak from my Evinrudes lower unit...

As outboardjim suggests, it could very well be accumulated exhaust oil because of a leaky exhaust housing seal or even a fracture in lower unit case.Most importantly ,you need to determine whether it is in fact engine oil or lower unit oil.<br />Your motor has two plugs for draining and changing oil in lower unit.A bottom drain plug and a top vent plug.You need to locate both of them to perform the procedure.The slotted head on these two plugs will look the same.They are on the starboard side of the lower unit,one near the top of the skeg and the vent plug is higher near the anti ventilation plate of the lower unit.Remove the bottom plug and the vent plug and drain the gear oil into a container where it can be examined for contaminants.You will be able to tell immediately upon it draining out whether it is laden with water as per description in earlier post.<br />Here's a diagram of the lower unit of a 1980 35 hp evinrude.# 31 is the drain and vent plugs. <br /><br />Lower unit.

 

[jonboatbassin]

Re: leak from my Evinrudes lower unit...

thanks for the help- now how do i fill it back up, with what, and how much? lol, im sure i sound ignorant and thats ok cuz i am to this. if you know of a site for just this info that i could go and read myself that would be great or if you know off the top of your head then that works,too.

 

[ob]

Re: leak from my Evinrudes lower unit...

Your lower unit takes marine Hi-Vis gear lube specifically for outboard lower units.you can either get penzoil from walmart in tubes or buy it from a John/Rude dealer.Two 10 oz. tubes will do your job.With the top vent plug removed ,fill from the lower hole rolling the tube until it is empty.Install the second tube in bottom hole until gear oil weeps from top vent hole.install both plugs with new seal washers that can be got at a dealer and your finished.That is providing the old oil drained is not water contaminated , in which case you'll need to determine which lower unit seal is leaking and either repair it yourself or have it repaired.If you are new to outboard maintenance, as you imply, I highly recommend obtaining a sevice manual before attempting any troubleshooting or repairs.

 

[Boatist]

Re: leak from my Evinrudes lower unit...

JonBoatBassin<br />I do not belive you have a problem at all. This oil you see is just normal unburned engine oil. If it is dark blackish and smells burnt it is very normal, usually get more oil on day when run at slow speed or trolling or if have too much oil in fuel. It will leak out the hole and also around the prop. This does not mean you have a crack case or bad seal it is normal. The reason the oil is black is because it has exhaust mixed with it.<br />Never hurts to check your lower unit oil if it has not been done lately. When refilling I have never had to use more than one tube on a small outboard. Fill from the bottom hole until runs out the top hole. Put the top plug in first. This will create a suction and slow the oil coming out the bottom hole when you remove the fill tube. Put the drain plug and you are all set. Oil in lower unit can be different colors depending which oil you use, but usually kinda honey colored. White Or Milky or with beads of water then You have a leak. Lower unit leaks most of the time is the prop shaft seals or the fill and dran hole washers. Good luck but Black oil is normal.

 

[karlp]

Re: leak from my Evinrudes lower unit...

jonboatbassin<br /><br />I had a similar problem with my 1978 70HP Johnsons (two). I found that when I stopped running the engines a dark fluid would drain from around the props. I checked the gear oil and it was clean but had the seals replaced anyway. This<br />discharge continued until I realized I had been using a 24:1 mixture instead of the 50:1. You may ask why the 24:1 and I can only attribute it to old age. It has taken me some time and many 50:1 fuel additions to burn the higher oil mixture from my tank. But now the tank mixture appears correct and no more leakage. So I would suggest that you double check on the oil ratio in your gas.

 

[oldboat1]

Re: leak from my Evinrudes lower unit...

best guess is that it is exhaust oil, and probably will stop with use (and the right fuel mix). If you let a little of the lower unit oil out and it is a normal brown color (or honey-colored, as mentioned above), I think I would screw the drain plug back in and run the engine a little more to see if the problem takes care of itself. By the way, leave the phillips head screw alone when searching for the drain plug on the bottom of the gearcase.

 

[Boatist]

Re: leak from my Evinrudes lower unit...

JonBoatBassin<br />One more thing that will cause you to see more exhaust oil is if the thermostat is stuck open and engine running cold.

 

[jonboatbassin]

Re: leak from my Evinrudes lower unit...

thanks alot for the input guys. i'll probably go ahead and change out the lower unit oil/lube this weekend just because it cant hurt. i'll be sure to mix the right ratio next tank i fill up and i'll see if the leak stops.<br />thanks again

 

[jonboatbassin]

Re: leak from my Evinrudes lower unit...

well i got a couple things of lower unit oil from walmart but the way you guys talk about filling it i dont see how it will work. the stuff seems to have the consistency of motor oil so how am i supposed to fill from the bottom hole without the crap all coming right back out before i can plug it? also, why cant i put the bottom plug in and fill from the top until it reaches the top hole? isnt this filling the same amount?<br />thanks again for the help.

 

[Boatist]

Re: leak from my Evinrudes lower unit...

Jonboatbassin<br />The oil should be 85W/90 and yes it will run out the bottom. The reason you fill from the bottom is much eaiser and will leave no air pockets. The key to filling is fill from bottom until oil reaches top hole. Then put the top plug in tight. This will create a suction so when take out tube not much oil will come out. This is just like when fill a glass of water and put some carboard over glass then hold the carboard and turn glass up side down, let go of carboard and water stays in the glass. If fill from the top may take hours to get full and even then could have air pockets.