Inspection of exhaust shutters on mercruiser 260

[boat_crazee]

This problem/question is regarding a 1979 Fiberform with the original Mercruiser 260 and an MR/Alpha outdrive, fresh water cooled. Thanks to the forum for all the posts on "water in the engine" as I was able to locate the leaky starboard exhaust manifold.<br /><br />Now for the question. With the manifold off, I wanted to assess the exhaust shutter on the starboard side to see if it was there and working. I see from other posts that there is a few opinions on exhaust shutters and their criticality. As the boat is in the water, I figured I could look down the exhaust bellows and be able to tell something. Well, the water level was raising and lowering slowly as the boat rocked at the dock. So I'm looking to confirm my thinking that the exhaust shutter is either gone or possibly stuck open? (Are they normally closed with the engine off?) And secondly, that the water movement indicates a free flow condition through the exhaust system? Thanks in advance for any insight you may have.

 

[Don S]

Re: Inspection of exhaust shutters on mercruiser 260

From the sounds of it, you replaced the bad manifold but not BOTH manifolds. If one was that bad, the other is right behind it, plus the old one may overheat because it's plugged up a lot more than the new one. <br />As a rule, if a manifold is bad. Replace both manifolds and both risers at the same time.<br />The shutters are right at the top of the Y pipe, and they should close the opening when the engine is off, the exhaust is what is supposed to open them.

 

[djvan]

Re: Inspection of exhaust shutters on mercruiser 260

On my alpha 140hp they hang open, water pushing from the aft closes them. At least that's how I see them working, they are cheap so why not inspect (replace) them once in a while?<br /><br />DougV><br /><br />edit; Don is right exhaust pushes them open

 

[crazy charlie]

Re: Inspection of exhaust shutters on mercruiser 260

If you cant see the shutter then it may be gone.At the top of the y tube it should be VERY visable and you should be able to see a very small hole with a hinge pin in the top of the tube that the shutter hinges on.They are very important and very cheap to replace.They stop water from backing in to the exhaust.I would not leave the dock without them and there are many here that dont find them important.If the $30 or so that they cost MAY save my motor,THEN SAVE MY MOTOR Charlie

 

[cc lancer]

Re: Inspection of exhaust shutters on mercruiser 260

Crazy Charlie:<br />I have read more complaints on this forum about Hydo-lock, than I have heard in my life.<br />These shutters have to be a big part of these problems.<br />I recently received a picture where the shutter had been spinning in the pipe. The holes on either side of the pipe had been hogged out so bad they were leaking water.<br />I have run 35 MPH in the ocean.......and stop, even with a following sea, water coming up high on the transom, I never have took water in my engine.

 

[boat_crazee]

Re: Inspection of exhaust shutters on mercruiser 260

Thanks for the feedback. The PORT exhaust manifold was recently done by a shop and it was quite an expensive job, so I'm doing the work on the Starboard manifold myself.<br /><br />I read that the only way to replace the exhaust shutters on the Mercruiser 260 is with the engine out. Are there (2) shutters or just (1)?<br /><br />So for now, I'll try not to throttle down too quickly and I'll be watching for following seas. Thanks for your help.

 

[bigbrownbuku]

Re: Inspection of exhaust shutters on mercruiser 260

there is a shutter for each side. usually the shutter with age falls off but the shutter pin remains as it is trapped by the exhaust rubber. if the pin is there but no shutter it is possible it is stuck at the bottom of the y causing a blockage. if there is no pin then chance are someone removed it previously. there are other ways to overcome water entering through the exhaust, volvo have a good system.

 

[rebars1]

Re: Inspection of exhaust shutters on mercruiser 260

In my 1971 mercruiser 888 v8, the shutters are down at the bottom of the Y pipes by the transom plate. The only way to check/replace them is to pull the engine. I envy those who have them at the top of the pipes!

 

[crazy charlie]

Re: Inspection of exhaust shutters on mercruiser 260

CC Lancer,the only PROBLEM with exhaust shutters is the LACK of.They are there for a reason,the manufacturers didnt have extra parts hanging around and decided to put them somewhere for the h3ll of it.They serve an important purpose.Just because YOU do a rapid throttle down in a following sea without engine trouble does not mean you should give advice and say it is ok to do.Many boats can get away with a maneuver like that and many cant without catastrophe. Charlie