Lower Unit Oil Change
Welcome to the step-by-step guide to changing your outboard's lower unit oil. This 8-step process is all it takes to ensure the oil in your lower unit is properly maintained.

The only tools required are a flat-head screwdriver and an oil drain pan. The entire process only takes 10-20 minutes. We recommend you change your lower unit oil at least once a year depending on how heavy the usage is of your outboard. Any brand of oil that meets the specification of API GL5 SAE 80 or 90 weight will work. You can find suitable oil at your local marine dealer or automotive store.

The chart at the end of this guide lists the approximate amount of oil needed to fill the lower unit of each model currently offered by Tohatsu.







The only tools required are a flat-head screwdriver and an oil drain pan. The entire process only takes 10-20 minutes. We recommend you change your lower unit oil at least once a year depending on how heavy the usage is of your outboard. Any brand of oil that meets the specification of API GL5 SAE 80 or 90 weight will work. You can find suitable oil at your local marine dealer or automotive store.
The chart at the end of this guide lists the approximate amount of oil needed to fill the lower unit of each model currently offered by Tohatsu.
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You can use any brand of lubricant that has a grade designation of API GL5 SAE 80 or 90 weight. Make sure you do not mix different oil brands or weights. To refill the lower unit, insert the bottle/tube into the BOTTOM drain hole. Then slowly squeeze the bottle to force the oil into the lower unit. |
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| WARNING: Running your outboard without completely filling the lower unit with oil to the proper level will cause severe damage to your outboard. See the comments at the end of this guide on how to check for the proper oil level in your lower unit. Be sure and properly dispose of your old oil by taking it to an oil recycling center. Most "quick lube" oil change centers or auto service stations will accept your used oil for a nominal fee. Comments: To check your oil level, remove the top oil plug, insert a small piece of wire straight into the top hole approximately 1 inch and withdraw the wire. If oil is on the wire the oil level is correct, if not the unit must be refilled to the correct level. To add ("top-off") oil install the top plug again, remove the bottom plug and put your oil bottle into the hole. Remove the top plug to release the vacuum and add the necessary amount of oil. Reinstall the top plug, then quickly reinstall the bottom plug. Check the oil level once again as described above. |
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