PartsVu.com is happy to offer a broad selection of Yamaha outboard thermostats, water pump repair & cooling components to match the exact specifications of your Yamaha outboard motor. If you have questions about performing maintenance on your outboard, chances are you’ll find the answers in our blog.
We also regularly release new helpful resources like:
Yamaha Outboard Thermostats, Water Pump Repair & Cooling Components FAQs
Yamaha lower unit gear lube is drained by removing the lower drain screw first and then the upper plug vent to allow air in. On most models, both plugs are clearly visible on the lower unit, but on models with low water pickups, the forward pickup will need to be removed to access the drain plug. Use a properly sized screwdriver assisted by a wrench if necessary to loosen these screws which should be pretty tight. An impact driver and hammer may be needed depending on who serviced your engine last. The drain screw has a magnetic tip, so inspect the plug after removal to see if heavy deposits exist. Some fine shavings are normal, but chunks or a large quantity of metal is cause for further inspection. Have a drain pan and extra rags handy as gear lube will begin running down the skeg as soon as you remove the upper vent plug. Be sure to collect the fiber gaskets from both plugs after removal, as these are not reusable and should be discarded.
Allow several minutes with the engine tilted all the way down to fully drain the old gear oil. Like your engine oil, inspect the spent oil for evidence of water intrusion or other contamination or metal. If you have purchased one of PartsVu’s handy lower unit oil change kits you will already have new gaskets, oil, and a pump. Screw the pump into the lower drain hole and then connect it to the quart of Yamalube gear oil or HD gear oil depending on your model. Begin pumping oil into the lower unit until oil begins to flow from the vent plug at the top. Stop pumping and wait a few minutes for all the air bubbles to work themselves out of the gearcase. After this brief pause, pump a few more pumps until clean gear oil without bubbles is flowing from the vent plug. With a fresh fiber gasket in place, install and torque the top vent plug. Unscrew your fill hose from the lower drain plug and quickly swap in the lower drain plug with a new gasket. Torque to spec and re-install the lower water pickup screen if applicable.
How do I perform a visual inspection of my Yamaha outboard lower unit?
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 prop shaft 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.
Since you are in the neighborhood – take the opportunity to lube your prop shaft, bearings, and any other wear points – Yamalube Marine Grease is good – use it!
How do I use Yamaha outboard schematics?
Looking for even more specific and in-depth information for maintaining or repairing your Yamaha outboard motor? PartsVu offers Yamaha Outboards Engine Schematics. By clicking on this link, you will be taken to Yamaha’s schematics page. Once there, you will choose the right parts for your Yamaha by searching either by your outboard’s Primary Identification Number (PID) located at the top of this page or look up your model using a series of dropdown menus on the left side of the page.
What is the life expectancy of my Yamaha outboard engine?
Yamaha outboard engines have a strong reputation for reliability, and for good reason. Your outboard engine life expectancy, at minimum, is about 1,500 hours (or, 6-8 years for the average boater). However, a properly maintained outboard engine can last more than 4,000 hours! This means that your engine could last for 16-21 years before needing to be replaced.
Shop for the boat parts you need with PartsVu and reference our Marine Tool Kits guide to learn about the tools essential to your engine maintenance. If the troubleshooting guide above provided no results, consult a mechanic. They may find the issue, or you may need to replace your outboard altogether.
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.
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 it 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.