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Check it out.
Visually inspect the exterior of your lower unit for any signs of damage
every time before you go out. If you fish, it's a good idea, every fifty hours
or so (or when necessary whichever occurs first), to remove the propeller
and check for any fishing line or other debris that may be wrapped around
the propeller shaft, which can cut into prop shaft seals and potentially
allow water to enter the gearcase. If found, visually inspect the propshaft
seals for damage or leakage. Then check the color of your lower unit
lubricant by cracking the "drain screw" on the bottom of the bullet and the
"vent screw" on the side of the lower unit. Allow a small amount to drain into a clean container. If
the lubricant is milky in color, you've got water in the lubricant. Have the lower unit seals inspected
by your Yamaha Marine dealer through a pressure test, and if necessary, have the seals replaced.
Pressure testing a lower unit is best performed by an authorized Yamaha Marine dealer, because
depending on findings, it may be necessary to disassemble the lower unit for further inspection.
Note: It's best not to run the outboard right before checking the lower unit lubricant, as this will agitate the oil with
whatever air is trapped inside. The resulting fine bubbles might be confused with the milky appearance that occurs
with water ingestion.
Change it out.
Yamaha recommends replacing your lower unit lubricant after the first 20 hours for a new outboard,
then every 100 hours after that. Also, if it's milky in color or smells or looks burnt when you're
checking it, it's time for a change. To do it yourself, place a pan under the bottom drain screw,
remove the screw, and then remove the upper vent screw on the side of the lower unit. Allow all of
the lubricant to drain into the pan. While you're waiting, check the drain screw. It's magnetic; so
any metal particles or shavings present in the lubricant will be attracted to it. Fine metallic dust is
normal, but if you find larger chips of metal on the screw or in the pan as the lubricant drains, have
your local Yamaha Marine dealer check for possible internal damage. Also at this time, replace the
small crush washer present on each screw (commonly known as "drain plug gaskets"). If you don't
see one, it may still be adhering to the outboard. Use a pick to pull it free, as these must be located,
discarded, and replaced each time these screws are removed.
Note: These drain screw crush washers serve as gaskets and are not reuseable. They are a main source of protection
against water intrusion into the lower unit, which can cause catastrophic dilution of the lubricant. Do NOT try to save a
few pennies here. Lower units are very expensive. It's best to always have some extra drain plug gaskets on hand.
Once all the lube has drained, refill the lower unit by threading the appropriate fitting into the lower
unit drain screw opening (on the bottom of the bullet) and slowly pumping in fresh Yamalube Marine
Gearcase Lube or Lubricant HD. Once you see this new fluid seeping out of the upper vent screw
hole, stop and wait 5 minutes, then very slowly continue pumping until it seeps from the vent screw
again. At this point, replace the vent screw with a new crush washer installed, and tighten according
to manufacturer specifications. Remove the fitting attached to the drain screw opening, and quickly
re-install the drain screw with the new crush washer installed. Tighten to factory specifications.
You may choose to do these procedures yourself, or you can have your
authorized Yamaha Marine dealer do them for you. Either way,
performing them is important for proper continued operation
and your continued satisfaction and enjoyment.
Note: All the items in this catalog are available through your local
authorized Yamaha Marine dealer. More information can be found
at Maintenance.YamahaOutboards.com.
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