Re: Rust Removal from Manifold
Gentlemen,<br />As a marine tech for most of my life, I can tell you that the number 1 reason without exception for a destroyed marine engine is the ehaust manifolds failing...hands down. Look in the discharge end of a manifold(or top of a center riser man.)You will see a large port for the exhaust in the middle surrounded by cooling passages...The center should be black and carboned up, the cooling ports usually rusty...if there is anything more than some minimal flash-rust in the center port TRASH IT!!! I REPEAT, TRASH IT!!!Flaking rust is a big red flag! Rust in the exhaust port is a clear indication that your manifold is leaking internally...bad enough while running, but when you shut down,the water runs into any cylinder which has an open exhaust valve...Cleaning an exhaust manifold is an invitation to catastrophic engine failure....and muriatic on cast iron is a big no-no, this will exacerbate any problem you already have and create problems you didn't have..DON"T DO IT!!! I have had several customers replace engines but just swapped the manifolds and destroyed brand new engines...a couple hundred bucks is a lot cheaper than a couple thousand for another engine....I pull the risers and check the ports once or twice a year,a five dollar gasket and some loctite 510 is a small price to pay to keep my engine safe...And even engines that have closed cooling are not immune from this problem, the raw water still exits via the exhaust system. Granted, salt water is harder on parts than say, lake water, but remember, even after you flush the engine on a trailer boat, the manifolds remain partially filled with water. Take a piece of cast iron and leave it out in your yard overnight if you want to see how long it takes cast iron to start corroding...In saltwater I see manifolds go away in as little as 2 years,fresh proportionally longer, but the fact that you mentioned that you have Log-style manifolds is the first clue that they are at the end of their serviceable life!<br />Do yourself a BIG favor and spring for new...<br />DON'T MESS AROUND WITH BAD MANIFOLDS ON A NEW ENGINE!!! If you don't want to take my word for it,ask any MARINE mechanic(not automotive)who makes his living repairing boats with more than a year or two experience...Seriously, bad manifolds make me way too much money...Don't let it happen to you...Good Luck and good boating.<br />Best Regards,<br />markvictor
.....JK
