splitting an SX drive

[CV16]

Prod # 3868891
SX-M. 1.60
Ser# 4202026798


Is there anything I should know before I take the bolts out to drop the lower half? The only thing I have found online talks about lifting the upper gear case off. I plan on leaving the drive attached to the boat and dropping the lower case.

 

[bruceb58]

Out of curiosity, why are you dropping lower Half?

 

[CV16]

I'm not getting any water up to the pump. Everything else has been gone through. I found a rubber part that a tube goes in wasn't making a good seal. I'll find out if that's it tomorrow.

 

[CV16]

#15 in this diagram is what isn't sealing. I ordered #13 & 15. This is the last thing it could be. If this doesn't get me water, I give up. http://www.volvopentastore.com/Lowe...on_id.831682849--store_id.366--view_id.782033

 

[gbeltran]

Hopefully that does the trick. I do have to ask, how are you testing? Was the boat in the lake? Or on the muffs with a hose?

 

[CV16]

Big bucket full of water. On muffs it would force water up. Only way to be sure is to let the pump do the pumping.

 

[bruceb58]

That's your problem. You never operate these in a bucket of water. Check your impeller. You probably burnt it up if you tried this at all. The pump can't pull up that far. when the boat is sitting in the water, the raw water pump is below the level of the water. When you are on plane, the water is forced into the inlets.

 

[gbeltran]

That's your problem. You never operate these in a bucket of water. Check your impeller. You probably burnt it up if you tried this at all. The pump can't pull up that far. when the boat is sitting in the water, the raw water pump is below the level of the water. When you are on plane, the water is forced into the inlets.

This should be a sticky...........that's why I always ask lake or muffs for a water issue.......
because many a time it's the bucket/tub test which doesn't work.

 

[bruceb58]

This should be a sticky...........that's why I always ask lake or muffs for a water issue.......
because many a time it's the bucket/tub test which doesn't work.

yep...I was going to ask the exact question. How many people start drives in tubs and wonder why it doesn't work?

These pumps are not designed to lift water.

 

[CV16]

Shouldn't it at least pull water from a bucket in the engine compartment? I took the hose off the pump and went to a bucket. I'd think it should pump. Also, I can't feel any suction from the hoses. I know the pump doesn't sit below the water line, The pump has to pull water up the way I see it.

 

[CV16]

And if I have to take the boat to a lake to see if the pump works, that could **** off lots of people. I would have to take up a spot at the launch just to see if it works, not to mention the $8 launch fee. If this is how Volvo Penta designed this, I will gladly go back to Mercruiser.

 

[CV16]

Also, I have read many posts on here that say the SX drive should not be ran on muffs. Water pressure from the hose won't tell me if the pump is working either.

 

[bruceb58]

A Mercruiser Bravo has the same issue. Unless you can get a bucket to get the water level up to the same level as the impeller, it's the same issue. That would be just as tough on an Alpha unless you have a huge bucket that you can get the cavitation plate under water.

Whoever told you not to use muffs on a Volvo is just plain wrong.

And yes, the impeller sits below the water line. If you pull the inlet hose while you sit in the water, water will come out. Depending on the year, the pump is either mounted to the crankshaft or belt driven at crankshaft level which is also the same level as the u-joint bellows which is also under water.

 

[CV16]

My cavitation plate is under water in my barrel of water. Also, the water line is below my motor, it does not sit below the water level on the lake. The way you describe it, you couldn't change the impeller while in the water without water coming in. I have changed mine in the lake with no water coming in.

 

[bruceb58]

The cavitation plate only needs to be under water on a Mercruiser Alpha. On a Volvo or Mercruiser Bravo it needs to over the u-joints.

When your boat is in the water your u-joint bellows is submerged is it not?

 

[spoilsofwar]

On a properly mounted engine and drive, the raw water pump will be below the waterline. You can change impellers in the water by plugging the inlet hose, or raising it above the waterline.

You can definitely run a Volvo SX on muffs. Most people just don't because the later models have the blue-cap hose inlet which is designed to let you run the motor on a hose without needing muffs.

 

[bruceb58]

Glad I haven't cleaned off my boat yet. See the water line on mine? Your water pump level is at crank level which is basically the same level as that trim sender.

EDIT...Spoilsofwar beat me to it!

 

[bruceb58]

I figured you would be glad we gave you this helpful information and you didn't have to waste your time splitting your drive for no reason.

Guess I was wrong!

 

[spoilsofwar]

If you want to know if there is an obstruction in the inlet tube preventing water from getting to the raw water pump, just pull off the tube and blow into it. It should be easy to do. This won't tell you if there is a leak in the inlet from the drive, but that problem only raises its head when the boat is up on plane and then it starts sucking air.

The water pressure of the hose, hooked up via muffs, will not spin the raw water pump impeller and simulate pump function, especially if the impeller is intact. If it's missing fins, like maybe all of them, and the water can just bypass the impeller and into the engine, then it might mess with your test. But otherwise, no.

 

[bruceb58]

The water pressure of the hose, hooked up via muffs, will not spin the raw water pump impeller and simulate pump function,

Agreed. I can turn on my hose to full 90PSI pressure and no water gets by the impeller. All leaks around the muffs.

BTW...use good muffs that supply water on both sides of the muffs like these:
https://www.amazon.com/Moeller-Flush...ller+Flushrite

MOD EDIT - Or HERE or HERE