How To's

How to change lower unit oil

How often should you change lower unit oil?

Most sterndrive and outboard manufacturers advise you to change the gearcase oil in your lower unit every 100 hours or once a year (whichever comes first). Clean oil is critical for protecting the heavily loaded gears in your lower unit and preventing expensive damage.

What kind of oil do you put in a lower unit?

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. into the BOTTOM drain hole. Then slowly squeeze the bottle to force the oil into the lower unit.

How do I change the oil on my lower end outboard motor?

Can you fill lower unit oil from top?

The smaller outboards should be filled from the bottom. The ones with the drain,fill and vent(bigger motors) need to be filled from the top.

Can I use regular gear oil in my lower unit?

So, can you use any old gear lube in your marine lower unit? If you want the best protection possible, and want your lower unit to last as long as your boat, then the answer is no. Consult your engine’s manual and look for the proper marine gear lube for your application.

Can you mix lower unit oil?

Important Note: Different gear oils cannot be combined. Each gear oil brand formula is unique; mixing two brands will result in a lubricant that is inferior to either of the two that you started with.

Why is my lower unit oil milky?

Milky oil means water has gotten into the lower unit. It is usually a bad propshaft seal, rather than a waterpump seal. But it is a job for your local shop. They’ll replace the seals and pressure check the lower unit.

How do I check my lower unit oil level?

How much gear oil does a lower unit hold?

One quart of gear lubricant or lower unit oil. A lower unit oil pump. Oil absorbent.

Do you have to drain lower unit oil to change impeller?

Yes, you will need to drain the lower unit fluid.

Is SAE 90 the same as 80w 90?

Yes it is the same close enough anyway. SAE 90 gear oil is equivalent to 50wt engine oil (SAE 80 = 30wt), so you could always dump that in instead if you want.

How do you flush a lower unit?

What color should my lower unit oil be?

A greyish milky color to your lower unit oil indicates water in the oil. Unless it is excessive, on an older motor, this is normal and why you drain it, and replace it, before it freezes.

How do I know if my lower unit is bad?

Bad outboard lower units can give the operator shifting issues, and other signs will include water in the gear lube, metallic particles on the drain screw magnet, clunking sounds when shifted, or the loss of the ability to shift into gears.

How do you clean the lower unit on a boat motor?

Simple Green Water Spot Remover works great for getting it off. Some say distilled vinegar in a 50/50 solution with water works as well but I haven’t tried that. Spray it down heavily, scrub it, then rinse THOROUGHLY. Then wax the midsection and lower cowling.

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