YSM12 Broken manifold

[Hermit Scott]

I sold my trusty YSM12 this weekend. I started her up after a month of not being ran to show the buyer how awesome this little engine is. I needed to turn the boat around so we could hoist the engine onto the dock. I was going to just do it by hand, so I cut the seacock off and was going up to shut down the engine. I started talking to Art(the buyer) and decided to do a Y turn under power to turn her around. I forgot to turn back on the water. While maneuvering smoke started coming from the engine. Then I remembered the seacock. Anyway we got her turned around, I opened up the seacock and ran her for a little while to make sure she was cooled down. When we started removing the motor Art pointed out some water leaking from the exhaust. I put my hand on the mixing elbow to feel around and the exhaust manifold broke in half! In fact it felt like it was just sitting on there. It wasn't the mixing elbow it was the solid pipe coming directly from the head. Of course I am telling art how awesome this motor was and the exhaust elbow is sitting there cracked in half. I don't know when or why this happened but I am glad it didn't happen while under way.
I don't know if not turning on the seacock had anything to do with it. After all the piece is solid cast iron. The motor mounts were wasted also. I replaced almost everything on that engine but the few things I didn't replace that I thought would be fine weren't.
So my boat is engineless until I get this 2QM20 rebuilt and then I will have to use a shoehorn to get it in.

 

[RAD88]

OOPS- Hope he bought the engine anyway.

What motor mounts did you use for the replacements on your YSM12?

DID you mount the heavier duty mounts at the stern or did you place them on the port or starboard side (can't remember) as mentioned on another post?

 

[Hermit Scott]

He did buy the engine. He drove 4 hours and stayed overnight to get it. The elbow is not that big a deal. I told him I would have one made in stainless rather than buying a stock one. That is what I am going to do on my rebuild on the 2QM.
The heavier part of the engine is in the front, but all the motor mounts were the same. I didn't replace them, I just cleaned them up and used them when I rebuilt and installed the YSM three years ago.
I don't have any motor mounts for this 2QM so I will be looking for some.
One other thing I was disappointed with was the paint on the engine. I stripped all parts down to bare metal. Used engine paint that is bake on. Then painted over that with high temp paint. It rusted through all that so fast. Maine Sail thought it was the sea water that I kept spilling on the engine changing the hoses. So I had sea water sitting in the bilge for a long time too. I cleaned the engine up and used a product called Rust Bullet. On some parts of the engine it held up, but where the block meets the head it lifted up and I was able to pull section off in sheets.
I think I didn't prepare the metal the right way before I painted it. I used acetone. I don't think that was enough. I will do more research before I do this block.

 

[Bill Roosa]

Hey Hermit
I can verify that acetone is not the recommended metal prep for rusty engines. The best solution is not getting sea water on the sucker in the first place but we are beyond that now. The only way I know to remove rust is sand blasting to bear metal, IMEDIATLY applying primer then painting at your leisure.
For the record a little rust (surface, not deeply corroded) will not affect your engine and unless you are taking folks on a tour of the boat and showing off the engine spaces you really are not going to get satisfaction cleaning it with fancy elixirs and ointments.
Rust never sleeps. If you do get salt water on your engine during an impeller change or such, do hose the entire engine space down with fresh water no matter how hard it is to clean up. You will not regret it.