Winterizing engine - dripless stuffing box

[Lshulan]

Hopefully my last post this year…. So do I need to do anything special when running antifreeze thru my Yanmar 370 hp that addresses the stuff box? I’ve heard that the hose from the engine needs to be removed and antifreeze poured in but if the shaft isn’t turning, will the antifreeze drain into the stuffing box? And if so, wouldn’t it drain from the engine into the hose anyway? Suggestions from owners that have this setup please would be welcomed.

 

[Pete Meisinger]

Your boats water pump will send antifreeze to the dripless stuffing box. Nothing else to be done.

If you run your boat on the hard in the spring you will see quite a bit of water coming out the shaft log.

pete

 

[SteveK]

Your boats water pump will send antifreeze to the dripless stuffing box. Nothing else to be done.

If you run your boat on the hard in the spring you will see quite a bit of water coming out the shaft log.

pete

Pete, please expand on your post. I am not following how the antifreeze got into the raw water system. And if you run your boat on the hard, where is the intake water coming from?

 

[DDW]

I assume you are winterizing the raw water system by pouring antifreeze into the raw filter while running the engine. This is the way it is ordinarily done. Most dripless shaft seals on powerboats have a raw water line coming from somewhere in the circuit to the shaft log to lubricate the shaft seal. When antifreeze is being circulated to the raw circuit, it will also feed the shaft log line, so you are done. Since a shaft log almost always slopes down, and the cutless bearing isn't watertight by design, pretty much all the water will drain anyway.

 

[DavidM]

On the Yanmar 370, there is a fitting on the after cooler that connects to the raw water side of the cooler. There is a hose on that fitting that supplies raw water to cool the dripless seal.

When you winterize, by dumping antifreeze in the open sea water strainer with its thruhull closed, the raw water pump sucks in antifreeze and pushes it through the engine's heat exchangers including that hose to the dripless seal. Sufficient antifreeze should be pushed through to fully winterize that gland. The gland should be nearly dry as sea water will drain out around the prop shaft and bearings when it is pulled out of the water, so it doesn't require much antifreeze coming through the hose to fully winterize it.

David

 

[Lshulan]

DavidM, Pete and DDW - thanks for the info, that’s great news, I was not looking forward to removing hoses or worrying about the shaft log being being damaged thru freezing.

 

[jleonard]

I've winterized with a dripless for 20 years. You can verify by looking at the cutlass/shaft area after you winterize. You'll see evidence of the antifreeze dripping out of the cutlass.
I always looked to verify.

 

[jgwinks]

Storing on the hard or in water? If on the hard all the water will drain out of the shaft log by itself so really nothing more needs to be done. I've never done in the water so not sure how to do that. Seems you would have to force the af into the box displacing the sea water but then what keeps it there?

 

[Lshulan]

Be storing on the hard. This is the first year I’ve had a Dripless shaft seal. I had read somewhere, not sure where though, about adding the antifreeze, but clearly based on all of the replies, this isn’t necessary. Thanks for the info

 

[jgwinks]

That makes it easier. I'd put some in there in case there's nooks and crannies that could hold water but it shouldn't take much. All my boats have had traditional stuffing boxes and I never did anything with them. They just drain themselves.