Inspecting BMT pt 8

[Fab1]

Check the lower unit gear oil.There's a fill and a drain screw.

Loosen the drain screw and let a little oil out to check it's condition.If the fluid comes out like this looking milky/coffee coloured water has at some stage breached the seals protecting the gears inside.(Not Good)

The drain plug has a magnet that is designed to capture tiny fragments of metal causes by the gears meshing together as they wear.(This is normal to see very fine paste like bits adhered to the magnet).Its big pieces/chunks you don't want.An example of the metal fillings on the drain plug.

Another thing I like to see is that the water inlet grills are still attached on the outboard and clear.

I did an impellor on a mates boat a few years ago that had disintegrated on him only to find that when I started his boat up after replacing the impellor the rest of the disintegrated impellor was lodged in behind this grill.

 

Next I like to check the Power trim and tilt motor and rams for corrosion and fluid leaks.

The motors themselves can corrode both externally and internally as well as the stainless rams.The motors can also have electrical issues but what we want to determine here is if they work and show any signs of the above as electrical diagnosis is usually well beyond the scope of the novice and is best left to the experts. 

I like to operate them through their full range of motion a few times with the switch and then checking the following.You can clearly see the rust here on the right motor and the base of the left ram.That rust will eventually eat through the motors case and the rust on that ram will destroy the seals causing hydraulic fluid leaks.

Here one on the left showing where rust had formed in the ram which will eat the seals in no time.This is where you'll commonly see any fluid leaks,right at the base of where the ram goes into it's cylinder.

Again check the condition of the fluid as they to can take in water through splashing etc.

When towing it's good practice to take the weight off the hydraulics by fitting a cut down roller or similar over the rams and lowering the outboards weight into these.

At home I would leave the outboard In the down position to retract the rams into their bores and periodically tilt the outboard through its full range of motion when stored for long periods of time to keep everything lubed and smooth.

I'll continue the saga in Pt 9.

Cheers.