lower unit oil change questions

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Fleet Admiral
Joined
May 26, 2009
Messages
9,715
I changed the lower unit oil in my 150 Yam TXRB this weekend.

The oil came out very black, and less than a quart drained out even though it holds 33 oz. (Yes, 33, so that you have to buy extra quarts to make it come out even, like the hot dog/buns quandary).
Should I be concerned about either the color or the amount? There was only a dusting of filings on the magnetic bottom screw. No signs of water, just black. I may have 100 hours on this oil.

Should I change it again soon--or after how many hours? I won't run it much after Jan. 1 until spring.

I keep it in the water so changing and even checking the level is difficult--or can you check the level while it's tilted up? How? If it's a little low can you add from the top hole at all?

I used a quart of Yam SAE90 first (not counting what spilled, lost in the pump, etc.) but then had to top off about 4 oz of SAE90 from West Marine--I know that generally you aren't supposed to mix brands but I can't see any harm in that--can you?

Changing it seems like the simplest job but what a mess; I've only done small motors before. I felt like the Valdez when I was finished. Of course the 25 mph wind in the parking lot (and 35* temps) didn't help. The pump I have doesn't screw onto a quart bottle and the tube doesn't reach the bottom. So holding it tight with one hand, holding the bottle with the other, holding the pump with the third and pumping with the forth doesn't work well for one guy with shoes on. And of course when you go to operate the tiny screws and slippery screwdriver, all the other stuff just falls over. Then there's mashing a quart bottle flat with one hand when I gave up on the pump. I'm going to use tubes next time even though it costs more, unless I find a refillable tube. And trying to find a day when the gravity isn't so strong.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,571
Re: lower unit oil change questions

It is not unusual for less gear oil to emerge when draining, that the full capacity. Since 33 oz is only 1 oz more than the qt it took to refill, I would say you got more then most.

Mixing the gear oil is not an issue, provided both are the same type (ie synthetic or dino). Get a new pump that fits a qt bottle. Pump it down 3/4 and then switch it to a new qt bottle.

The wind will spray the draining gear oil everwhere. The volume is so little, just do your best to clean it up.....
 

robert graham

Admiral
Joined
Apr 16, 2009
Messages
6,908
Re: lower unit oil change questions

Walmart sells those little hand pumps with the adapter that screws into your drain hole, drain your unit into an old plastic dish pan or similar container, pump it full until it comes out the top hole, replace the top plug, then unscrew filling adapter and quickly replace bottom plug. It's really not supposed to be all that difficult or messy. I don't know about the black oil thing, but if mine was black, I might be tempted to change it more often, say twice a year, instead of once. Does your old oil also smell bad?
 
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