Gearbox Oil Change

[MouseDog]

I wanted to take my boat to have the gearbox oil changed, but  everyone I have spoken to tells me it is quite an easy job to do so I do not want to spend money unnecessarily and want to attempt doing it myself.  Here is what I have been told:

There are apparently 2 screws that I must remove, that will drain the old oil.  After the old oil has been drained the gearbox must be filled from the bottom again, when the oil comes out at the top one, close that one, then the bottom one.

Is this the right way to do it??? 

I have located one of the screws, I presume it is the "top" one, just behind the prop is another screw, will this be the bottom one???

I'll post pics as soon as my camera's battery is charged

 

[shagnrelease]

Hey Mouse dog, thats 100% correct on the method there.
the screw heads are normally quite big and flat, and the bottom one should be at the lowest portion of the gearbox case, I suppose each motor is different.
Remove both the screws and allow all the oil to drain,there is a special adaptor that you can purchase to screw on to the gearbox oil bottles which makes it a bit easier,but they are not a must.Fill it up till the oil comes out the top plug, tighten it up,replace the bottom screw and your sorted.

 

[dugongboy]

Get lots of rags!!

 

[MouseDog]

dugongboy wrote:

Get lots of rags!!

Luckily there is an open piece of veld right accross the road from my house, rather going to do it there than in my driveway

 

[unathi]

Once stare at a mechanic using a primer bulb and pipe to fill the gearbox again with oil.

 

[Bliksem]

shagnrelease wrote:

Hey Mouse dog, thats 100% correct on the method there.
the screw heads are normally quite big and flat, and the bottom one should be at the lowest portion of the gearbox case, I suppose each motor is different.
Remove both the screws and allow all the oil to drain,there is a special adaptor that you can purchase to screw on to the gearbox oil bottles which makes it a bit easier,but they are not a must.Fill it up till the oil comes out the top plug, tighten it up,replace the bottom screw and your sorted.

I have this one. Worth every penny. The plunger screws on the bottle and the plastic pipe ends in a threaded adaptor that screws into the drain/filler hole.

 

[Sharkie Eye]

Hi MouseDog,

“Luckily there is an open piece of veld right accross the road from my house, rather going to do it there than in my driveway”

Nooooooooooooo, rather use an old 5l can opened at the side and drain the oil in there, where after you can dispose of it into a 2l Coke bottle and in the dirt bin. Pollution you know? <smile>

Also note, when draining the oil look at the color, if it’s very milky in color …… problem!

Water in the oil!

Could be because of screws not fastened enough, a screw washer problem, a gearbox seal gone or a driveshaft seal gone.

In this case I’ll advice you to let it be checked at a reputable mechanic.

First unscrew the top screw on the upper side of the gearbox usually on the starboard side of the gearbox, then remove the screw and close the hole with your thumb, whilst someone is removing the bottom screw also on the bottom side of the gearbox on the starboard side. Then close the bottom hole with your other thumb whilst positioning the empty container in place. You’ll notice very little oil will come out if you open the bottom hole only, until you open both holes then a stream of oil will exit the gearbox rapidly into the plastic can.

I always let my moter run for some time in gear at reasonable revolutions before draining the gearbox oil, just to heat up the oil a little before draining.

I also believe to replace the washers with new once every time before replacing the gearbox screws.

Good luck … very easy once you know how.
With kind regards

 

[Sharkie Eye]

Hi MouseDog,

“Luckily there is an open piece of veld right accross the road from my house, rather going to do it there than in my driveway”

Nooooooooooooo, rather use an old 5l can opened at the side and drain the oil in there, where after you can dispose of it into a 2l Coke bottle and in the dirt bin. Pollution you know? <smile>

Also note, when draining the oil look at the color, if it’s very milky in color …… problem!

Water in the oil!

Could be because of screws not fastened enough, a screw washer problem, a gearbox seal gone or a driveshaft seal gone.

In this case I’ll advice you to let it be checked at a reputable mechanic.

First unscrew the top screw on the upper side of the gearbox usually on the starboard side of the gearbox, then remove the screw and close the hole with your thumb, whilst someone is removing the bottom screw also on the bottom side of the gearbox on the starboard side. Then close the bottom hole with your other thumb whilst positioning the empty container in place. You’ll notice very little oil will come out if you open the bottom hole only, until you open both holes then a stream of oil will exit the gearbox rapidly into the plastic can.

I always let my moter run for some time in gear at reasonable revolutions before draining the gearbox oil, just to heat up the oil a little before draining.

I also believe to replace the washers with new once every time before replacing the gearbox screws.

Good luck … very easy once you know how.
With kind regards

 

[MOGGY]

Tip from an old fool.

Make sure that the cavitation plate is level, so that the correct amount of oils is put into the gearbox.

I check it with a spirit level.

 

[Patrick]

Used oil should be discarded in the same way that motor oil should be. Most municipal dumps have a ROSE oil collection facility at them.

Just a tip, but placing a piece of masking tape as a tab under the drain screw, hanging off the motor will assist the oil to find a straight path downwards to run into your container, rather than down the skeg when it feels like it.

 

[MouseDog]

Patrick wrote:

..... Most municipal dumps have a ROSE oil collection facility at them.

....

You obviously havn't been in Jeffreys yet, we don't have a municipaliy, we have a circus ran by a bunch of clowns.

Thanks for the masking tape tip.  I used an old laundry basket (without holes) and lowered the motor in that, then I opened the screws, the oil just ran straight into the basket

 

[Richard M]

The quicksilver gear lube pump noxxle does not fit on a 50HP yammie gearbox. The threads are different. Trying to change the oil without one of these pumps is a kak job. If you are going to do it yourself, get a pump and modify a nozzle to fit. It makes the job easy and quick. Trying to hold the oil bottle upside down whilst also holding the tube over the bottom hole is not fun. You will end up with more oil on the floor than in the g/box. Get the right tool for the job. I have asked a few boat shops for a lube pump for the yamaha, but they are not keen to sell them. So get the quicksilver one and make an adapter to fit your Yammie box. Its worth the effort.