Yanmar YSM12: Is salt buildup sign of bad gasket or normal

[FigBug]

Looking at a boat that uses salt water cooling. No experience with that. Is this amount of salt buildup on engine normal or sign of (head?) gasket leaking?

[Compass790]

I cant see around the cylinder head joint in yr pic but yr top cover with thermostat & anode in it that has the salt around it is definitely leaking. Easy to fix with silicone. These engines need flushing occaissionally with acid type desalting solution, there are you tube vids on how to do that.
There should be be no salting around any joints on the engine as it shows a leak.
I recommend using threadlocker such as loctite 242 or equiv on every bolt on yr engine as they vibrate a lot.
If the engine starts quickly & doesnt blow black smoke except on sudden throttle increase its unlikely the head gasket is blown.
Yr engine looks good for a salt water one of that era.
Gotta watch the exhaust elbows too, the design is bad in that when it fails it can drop salt water on top of exhaust valve & if its open......

[Wotname]

^^ wot Compass790 said plus 1.

[Emmalina]

And don't forget to give it a good wash after you fix the leak ! Probably just the hose clamp but take the pipe of and clean the tube before re seating.

[Lepke]

White buildup isn't always salt. It can be corrosion from dissimilar metals. A reaction between metal head gasket material and the cast iron. If there's never any visible water it may be corrosion or electrolysis.
It's common in some engines like older Detroits. They have runs of tubing from the SW pump to the HE in several sections separated by hose connections. Both the HE and pump have zincs but the immediate sections are unprotected. So corrosion forms at the hose. The solution is a grounding wire.

[Compass790]

Not looking for an argument Lepke , I'm sure you are more experienced than I am, what you say is right but in OP's case on his ysm12 I'd bet a bottle on it that his cover gasket is leaking. The engine anode is in that cover so it should, afaik, mitigate electrolysis.
We have a little sister engine ( YSM 8 ) and I know the problem.

[Compass790]

Just had a look at full size image, forgot how to do that previously. If thats your head gasket joint under the throttle cable lug/ bracket I can see salt crystals on that vertical joint. Also its quite rusty underneath that area. I would be suspicious that you do have a leaking head gasket. Have a look at it when engine is running & that may answer the question if you see steam or water squirting. If you pull head & replace gasket I'd recommend using permatex 51813 or loctite 515 or 518 on head gasket.
Another CF contributor claims the head gaskets on the ys8 hp only last 500 hrs without any gasket goo..

[LeeV]

Excellent comments above. If you are buying (or bought) this engine/boat, I’d recommend replacing the exhaust elbow(s) with SSteel versions. Don’t have the link handy but there’s a nice fellow and his daughter who sells them. Nice quality, and after having them on the cat we just sold for 4 years they were still in original condition.

This may be him: https://hdimarine.net/product/gm-sta...-mixing-elbow/

[bailsout]

LeeV, that is the correct link. I second your recommendation.

[FigBug]

Thanks for all the comments everybody. This is Yamaha 30 I'm considering buying. Just wanted to know if this is a show stopper before I even get a survey done.

[Compass790]

I wouldnt regard it as a show stopper if you are ok with doing yr own mechanical repairs
They aren't difficult to repair but if you pay someone to do it could get a bit expensive.

[chasfgr]

Having replaced a direct cooled Yanmar with a more current model (2gm by a 3YSM,
I would suggest that salt build-up from the headgasket is pretty normal, just look at the lamd width at the leak site!!


Direct cooled engines are really for freshwater use, the colant galleries wiill be indresingly ceked with rust.


I'm afraid the provision of rww-water cooled power units by builders is an attempt to reduce the cost and complexity of auxiliary power.
The inference is that you should be sailing your boat everywhere.

[Manateeman]

OEM boatbuilders come in two flavors. Build cheap to sell cheap or build Bristol fashion to compete with custom shops. I’ve worked for a lot.
Option one is to add a stainless exhaust...great idea...fix all the little issues...test to see if it is a bad head gasket..repair it yourself.
Option two. Minimal investment in engine...run it till it drops.
Your money, your choice.
Nothing feels as nice as a new engine in a storm.
We never use silly conn on anything.
Happy trails.
Mark