Jim,
There are ample opportunities for problems in the raw water cooling system. The easiest to check is the nipple on the exhaust elbow. If it was installed with some never seize lube, it should be easy to remove and check. They do tend to gum up with salt deposits from time to time. I always check the nipples first! The next most likely suspect would be a clogged exhaust elbow. I have removed mine in the past and cleaned it out with a coat hanger. No pretty, but it may buy you a year or two. Replacement is the best course of action, especially since you have it off already. I removed my heat exchanger and had it hot tanked a number of years ago. It wasn't in bad shape, but now I feel better about it. Good raw water flow will keep your exhaust quiet. That's how I can tell my system needs attention, by the change in sound. I switched from the SS stock muffler to a smaller fiberglass muffler a couple years ago. It sounds great. Not loud, but nice an mellow. Jake Jake Brodersen C&C 35 Mk-III "Midnight Mistress Hampton VA From: cnc-list-boun...@cnc-list.com [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of jim aridas Sent: Monday, September 10, 2012 9:33 AM To: cnc-list Subject: Re: Stus-List Yanmar question Engine question. Have a Yanmar 3GMF20. Noticed this weekend the exhaust started sounding "like its hissing or more air with the water". Last few weeks it sounded a little different, but thought that since my slip changed at the yacht club I back up close to a bulk head and possibly just more sound reflected back? But after a 2 1/2 hour motor to a race this weekend it sounded worse. Checked the strainer, clear. Jumped in the water, checked for blockage at the thru hull, clear. No overheating or temp alarm. Ran the boat back to my club after the race. Didn't need much engine it was a down wind run in 15 +, launched the kite, smiled and laughed the whole way home. (The dark and stormies didn't hurt either, till sunday am) I'll pull the impeller today and throw in a new one, its the 2nd season on the present one. Is this the sound when the exhaust elbow is carbon'd up ? Oh and btw have to brag. Won the race, blowing steady 25 with some shots peaked to 32. Wild fun ride, reefed main up wind, heavy air 130%, 7 people on the rail. Down wind .... the hull only lets you go so fast. Jim Galaxy 34' Brielle, NJ
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