Is this safe?

[donoharm]

Hello, I’m the new owner of an Atomic 4 powered C&C 30. While looking around in the engine bay, I noticed some corrosion on the engine block. The engine works like a champ, but I’m a little concerned about the level of corrosion on the block. My questions for the forum are:

1) Is this normal?
2) is this safe?
3) what, if anything should be done to remediate it?

[capnward]

Rust like that is normal with people who don't take care of their engine. It is safe for now, as long as it doesn't spray water in that area. You are right to be concerned about the level of corrosion. As long as your engine runs well, and is not leaking water from that corroded water jacket side plate, you might as well enjoy it this summer. But you will eventually need to remove the engine from the boat to deal with all that rust and repaint the engine. It would make a good winter project. There is probably plenty of metal left under the rust, but you will need a new water jacket plate. I suspect the reason for the rust is the side plate has leaked in the past, or the hose fitting into it. I am guessing you have a raw water cooled engine, and the side plate has been leaking salt water for a while. The block is probably still ok, but you will have to make sure. Change to fresh water cooling and corrosion like this is less likely.

[joe_db]

Safe as in won't blow up - sure.
You do need to get rid of the leaks causing that rust and then fix the rust

[Al Schober]

That leakage at the side plate is common, and is caused by the 8 bolts. It's nigh impossible to get the threads of the bolts to seal. Best fix is to change to studs and nuts. Our host sells a kit for this job. When the plate is off, you can evaluate the degree of corrosion on the back side (plan on replacing it).
I notice our host is sold out on the stud kits. Make up your own kit from some stainless set screws, stainless nuts, and some JB Weld.

[Surcouf]

Welcome!

as mentioned by the others:
- not unsafe
- can "easily" be recovered to a very good state: at the end of the season (do not waste a single day out of 2021), be ready with the proper material (new plate + stud kit etc...). Remove alternator + starter, clean / brush / chisel out the rust, treat rust, paint, and install new plate with Permatex etc.. There are many threads on this forum that will show much more rust (way more sometimes), and help you perform that very satisfactory repair.

the absolute key on the A4 is to treat and solve any leak, to prevent sea water from rusting the block.

our host will also help you on supply, parts etc...
Good luck