Draining engine oil

[BlackRapids]

What's the best way to drain engine oil (from reservoir / engine) from a 1987 Yamaha 90 outboard?

[boscoe99]

Disconnect the hose that leads from the tank to the oil pump probably.

[DennisG01]

There wouldn't be any engine oil with that engine. It's a 2-stroke. Do you mean the two cycle oil? Suck it out with an oil extractor would probably be the easiest. Or you could disconnect the lower feed hose. Is the oil bad?

[BlackRapids]

Yes the oil is bad. Two stroke oil, you are correct. I think your recommendation is the way to go. I've been looking at a few pumps on line for under $50; one manual pump into a can for $44 and an inexpensive electric for just under $30. If I disconnect the tube connecting the oil reservoir to the oil pump, looks tough collecting the oil. It likely will go everywhere. Is there a screw/valve or something to drain the oil already pumped? Or is it too late to drain that out? Separate subject. Is there a DVD/video series which shows how to conduct maintenance on these older 1980s Yamaha outboards (ie winterization, fuel/oil filter replacement, water pump, etc)? Thanks. BR

[99yam40]

I thought the motor oil tank on Yamahas had a water trap/drain you could use to drain the oil out of it with, but I have not even looked at one from that year range.

I am sure there have been a lot of people have made videos of stuff with their motors, but do not know of any technical videos made by Yamaha

[boscoe99]

I thought the motor oil tank on Yamahas had a water trap/drain you could use to drain the oil out of it with, but I have not even looked at one from that year range.

I am sure there have been a lot of people have made videos of stuff with their motors, but do not know of any technical videos made by Yamaha

I looked for a drain sump. Used on V4 and V6 motors but apparently not on a 90 that uses an engine mounted oil tank. In lieu of removing a plastic sump (which I don't see being used) it would be just as easy to remove the hose that connects to the bottom of the tank and which runs to the oil pump. There is another hose on the bottom of the tank that could also be removed if it is easier to get to. But if the hose is removed at the pump then all of the bad oil can be removed from the system.

Better to drain old oil from the bottom than to try and suck it out from above IMO. That way it can all be removed. The tank can even then be flushed with a suitable fluid if needed. In addition, the sensor does not have to be removed. Removal and reinstallation of the sensor can result in the seal at the top becoming less effective, which leads to an oil leak when the motor it tilted up.

[99yam40]

I do not see that second hose on the 90ETLH parts breakdown here ,1987 90ETLH Yamaha Outboard OIL PUMP TANK Diagram and Parts

where did you get that part breakdown from?SM?

What was the purpose of that hose that just runs from the top to the bottom of oil tank?
I figured that would be a drain line

[boscoe99]

I do not see that second hose on the 90ETLH parts breakdown here ,1987 90ETLH Yamaha Outboard OIL PUMP TANK Diagram and Parts

where did you get that part breakdown from?SM?

What was the purpose of that hose that just runs from the top to the bottom of oil tank?
I figured that would be a drain line

I used a later illustration for clarity. It is from the Yamaha parts catalog but it is from a 90TLR.

I noted it uses two hoses whereas the older one uses just one. The reason for the second hose is unknown to me. Might be something to do with venting the tank???

It could be used as drain line. Many ways to skin the "drain the oil tank" cat.

[DennisG01]

Many ways to skin the "drain the oil tank" cat.

Couldn't agree more.

One could use the oil extractor tube through the top cap - shouldn't be to hard to get it into the corners. But, you could also pinch the feed tube/plug it's mating nipple - and it's not all that hard to remove it. I do like the idea of cleaning out the feed tube as well, though.

Black, if you go for the oil extractor route (which is a good tool to have around, anyways) I would skip the cheapie 12V ones - they're kinda "hit or miss" as far as how long they last. I've had a MityVac 7201 for about 6 or 7 years and it gets used harder than the average DIY'r, only because I do winterizing on the side. Now, there are some REALLY nice 12V ones that will last decades - but they are in the $150-$200 range - more than most would want to spend.

[TownsendsFJR1300]

I bought a cheap (under $10.00) pump (made for oil) that attaches to your drill motor. It drained 5.5 quarts of 10w30 in less than a minute.

I looked for the link but couldn't find it.


Is it a big PIA to remove the tank and just flip it upside down, maybe flush with brake cleaner?

[rodbolt17]

in 20 min you can simply remove the tank,dump it,wash it out and reinstall it.
the pump is self bleeding,thats the second hose, and go play.
myself I like to run a gallon or so of premix anytime I reassemble any oiling system to insure its oiling.