Can sail drive lower unit oil be sucked out?

[Quickstep192]

Is it possible to suck out lower unit oil from a SailDrive using a vacuum pump from inside the boat?

My vacuum pump has a long skinny tube, but I’m guessing it can’t get all the way to the bottom.

Also, I tried using it to suck trans fluid from my powerboat and got it stuck in the baffles. Not eager to repeat that. Stop me before I fuck up again.

 

[Zonker]

Volvo?

Step 1. Hire a crane

Step 2. Invert boat.

Step 3. Drain oil from inside.

Actually since about year 2000 (?) you can change Volvo from inside.



Some Yanmars have a 2nd port that you use compressed air to blow out the oil.

Or pump out by hand pump

 

[LewSipfher]

Is it possible to suck out lower unit oil from a SailDrive using a vacuum pump from inside the boat?

My vacuum pump has a long skinny tube, but I’m guessing it can’t get all the way to the bottom.

Also, I tried using it to suck trans fluid from my powerboat and got it stuck in the baffles. Not eager to repeat that. Stop me before I fuck up again.

I use an extractor with the longest, skinniest tube available, patience to get the tube to the bottom of the drives, and measure what I extract to check that I gat all.

Volvo 120S drives from 1992.

 

[MiddayGun]

I used a vacuum pump to do the job on my 120s, you need a fairly skinny pickup hose.
And it takes quite a while as (at least in mine) its 15/40 engine oil, which is pretty viscous when cold.

 

[DDW]

My (2006) Volvo 150S saildrive (actually built by ZF-Hurth) has a tube to the bottom of the drive specifically for this purpose.

 

[ryley]

if it's an SD20, you have to drain it from the outside. from the inside you only get about 1/3.

 

[David J Cooper]

I ran a fleet of charter boats in Vancouver a few years ago. We often pumped the oil out of our boats with Volvo saildrives through the dipstick.

It wasn't pefect but is better then leaving old oil in there. Of course doing it through the bung on the bottom is best. You can also check for metal particles on the plug as it is magnetic.

 

[Zonker]

So do it 3 times; suck/refill/run the engine for a few minutes and repeat. Should hold you until the next haulout.

 

[ryley]

So do it 3 times; suck/refill/run the engine for a few minutes and repeat. Should hold you until the next haulout.

here's the problem with that method (which I've done). If there is water in the oil, you're only sucking the oil out, not the water. although if you do it soon enough after running the engine, it does emulsify enough that you get some of the water as well.

 

[Monkey]

here's the problem with that method (which I've done). If there is water in the oil, you're only sucking the oil out, not the water. although if you do it soon enough after running the engine, it does emulsify enough that you get some of the water as well.

Well, then just fill the whole thing with water. That way you’ll know you’re sucking the water out! 😁

 

[Frank Stich]

You don’t mention what type of sail drive on your boat. We have 2 Yanmar SD60s and a 12 v pump with a 1/2” ID hose that we hose clamp to the suction tube on the saildrive and are able to pull out every drop and then more with our 12v pump. Very easy.

 

[Quickstep192]

Mine is an SD20.

This may only further demonstrate my inexperience, but there are two sets of gears on this thing, right? The upper that goes from horizontal from the engine to vertical in the shaft and the the lower gear case that goes go from the shaft horizontal to the prop.

I can’t see how pressurizing at the top would push oil up from the lower unit.

Am I missing something?