Can you change the oil in a lower unit WITHOUT having an oil pump?

Wormy_1709

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Oct 26, 2012
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I have a 15hp Chrysler Outboard. I want to change the oil in the lower unit, but i cant find an oil pump fitting that will fit my engine. I was wondering if you HAVE to use the pump or can you just drain it, put the bottom screw in and just fill it from the top screw hole till it starts pouring out? Basically the same concept as changing the fluid in a transmittion. Any help would be appreciated. Thanks.
 

coolbri70

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Re: Can you change the oil in a lower unit WITHOUT having an oil pump?

I believe it has to be filled from the bottom up
 

Capt Ken

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Re: Can you change the oil in a lower unit WITHOUT having an oil pump?

You can buy the squeeze tubes and squirt it in from the bottom till it comes out the top hole.
 

Frank Acampora

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Re: Can you change the oil in a lower unit WITHOUT having an oil pump?

OR----You can lay the engine on its side and dribble oil in the top hole until it reaches the level of the hole, then plug it. Very slow and not really good technique, but you asked.
 

MickLovin

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Re: Can you change the oil in a lower unit WITHOUT having an oil pump?

On mine there is a vent hole so you can actually fill from the top not that I do but, as they say buy a squeeze type oil filler, but for the cost it's easier with a $20 pump
 

phillyg

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Re: Can you change the oil in a lower unit WITHOUT having an oil pump?

All lower units I have ever seen, both outboards and I/Os, require filling from the bottom up, never from the top. I think the reason has something to do with not getting enough fluid in from the top because of air pockets. Use a pump.
 

gregmsr

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Re: Can you change the oil in a lower unit WITHOUT having an oil pump?

If it holds one quart and you get one quart in it, it is full. I believe you can fill from the top if you have to, just go very slow and let the bubbles/air pockets disperse. Might take a few hours, fill a little, let it set, fill a little.....my 2c.
 

MickLovin

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Re: Can you change the oil in a lower unit WITHOUT having an oil pump?

If you have a vent plug as well as a fill plug you can fill from the top, with my 100hp it has both and I fill from the top with the same result of oil coming from the vent when full, when I had my 75hp I filled from the bottom on my 76 model as it only had the fill and drain, but on my 80 model it had vent, fill and drain. So I undo the vent and drain it out then close the drain and fill through the fill hole the air comes out through the vent hole and when it's full, just like the two hole gear boxes it will come out the fill hole or the vent when full. If you only have the drain and fill holes fill from the bottom.
 

oldboat1

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Re: Can you change the oil in a lower unit WITHOUT having an oil pump?

It's a bottom-up procedure to displace air. I leave the vent plug on top threaded in slightly so I can tighten it down quickly and make less of a mess after oil seeps out the vent hole. If the lower unit is well sealed, tightening down the vent screw stops or virtually stops oil in a full gearcase from running out the fill hole. I would really suggest finding a pump, as it's much less messy (my experience) than tubes. The universal fitting (plastic) on the pump should fit nearly any lower unit, so I'm surprised you don't have a fit for your 15. The fit on my 10 is fine. Maybe you aren't inserting the pump screw at the right angle. The fill hole is coarse threaded, like the pump screw, and might come in tilted slightly upward -- thinking you might be missing the insertion angle?
 

jerryjerry05

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Re: Can you change the oil in a lower unit WITHOUT having an oil pump?

Not sure where your located but every place that sells outboard oil and gear oil will have a pump kit somewhere.
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.
I fill till it pukes from one side then fill it from the other till it comes out the fill/vent.
 

MickLovin

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Re: Can you change the oil in a lower unit WITHOUT having an oil pump?

Thanks Jerry jerry exactly what I do for the ones with a vent in. It's obvious this is the reason for the vent so it can be top filled. But a lot of other makes big motors still have the 2 hole system so they are bottom fill too, it is only the vent,fill and drain gear boxes you can fill from the top.
 

Big Fish Billy

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Re: Can you change the oil in a lower unit WITHOUT having an oil pump?

And you should be doing it every Fall, at least, to be sure water that may have gotten by the seal is drained out for the Winter. And as we all know, if it's easy, we're more likely to do it....so invest in a little pump for $5 that will fit on your quart of gear oil.
 

ssmith386

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Re: Can you change the oil in a lower unit WITHOUT having an oil pump?

I got my pump for pretty cheap at wal mart. If you don't have two top holes like some do (mine doesn't) youll need to fill from the bottom to avoid air bubbles.
 

oldboat1

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Re: Can you change the oil in a lower unit WITHOUT having an oil pump?

apologies to Mick and sssmith for missing this one. I've never had the larger motor with the three(?) plugs.

recommend the pump if there is one that fits (that point still has me a little baffled). It's a little less messy, but it also strikes me it's more accurate. I can never get the full tube of oil squeezed out into the unit, but probably technique.
 

Frank Acampora

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Re: Can you change the oil in a lower unit WITHOUT having an oil pump?

As Jerry said, almost every pump sold fits the hole. Want a screw-in fitting? The plug is 3/8 X16. Drill a standard 3/8 bolt and use it on the end of the pump hose.
 

jpwilly

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Re: Can you change the oil in a lower unit WITHOUT having an oil pump?

Got a outboard pump a walmart today for $6.97 with 1 qt of quicksilver gear oil $11.97. And did the gear oil change tonight. Was simple and cost less than $20. there was just a little milky oil dark grey that came out at first then it came out dark blue so some water did get into mine but didn't seam like much.

I've changed mine before with out a pump on an I/O once I filled it up I used the trim to crank it up and down a few times and topped off again. Worked fine.
 
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oldboat1

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Re: Can you change the oil in a lower unit WITHOUT having an oil pump?

hey -- glad to hear the change went well, jpwilly!

got a little resistance today on the J & E board when I called that Quicksilver lube black. (Lister was worried that his lower unit oil was black, and I was suggesting it might be the Quicksilver.) I hereby affirm it is blue-green, and not black. I was wrong.

But it looks black. I think I prefer the lighter colored stuff, if given a choice, because it might be a little easier to see contamination -- other than water, I guess, because that should come up looking something like coffee with creme. Additionally, if there is a leak onto the lower unit, it might be kind of hard to distinguish the dark oil from the black exhaust residue. But I still have a couple quarts of Quicksilver, and will use it. Kind of take what's available.
 
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jpwilly

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Re: Can you change the oil in a lower unit WITHOUT having an oil pump?

Yea you definitely need to ensure you eliminate the air pockets but up and down a few times on the tilt did the trick for me. The Quicksilver is indeed dark blue green and contamination shows up as black grayish color. Outboard dumped around 4OZ of the mixed dark gray out the bottom fill plug before the correct color came out. I just got the boat so don't know this history of the gear oil. There was no fishing line when I took the prop off. I filled it up with the new oil and made sure the screws were nice and tight. I'll keep an good eye on it - might have to change the seal might not.

Anyone know how much water getting in is considered normal on a 20 year old lower?? How many drops of water does it take to contaminate 4oz of gear oil?
 

Jiggz

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Oct 23, 2009
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Re: Can you change the oil in a lower unit WITHOUT having an oil pump?

I find it amazing it generated this much discussion for a gear fluid pump costing less than $10.00 that you can use more than once. With the price of gas constantly above $3.00 it makes one wonder if owners even ran their boats anymore.
 

coolbri70

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Re: Can you change the oil in a lower unit WITHOUT having an oil pump?

I bought a pump online, all it is, one of the pumps that comes on a bottle of lotion or hand soap, with a rubber hose shoved over the end, and a metal threaded fitting at the other end. does a great job
 
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