rusty/corroded hose clamps and a possible failed IAC valve

[julians]

I have 5.0 mpi in my 2006 200 select, it has 255 hours on it. But recently I have been suffereing from a series of failed hose clamps on the cooling system, causing overheating. It seems like the standard merc hose clamps whilst being stainless steel are pretty thin metal , and have holes for the screw to tighten them, these have rusted and failed. I have now had 3 fail.

I have now replaced all the hose clamps on the engine with thicker stronger clamps, so hope to have cured my issues. Has anyone else had this problem? My boat is used exclusivly on the sea, so I guess they will corrode faster than afresh water boat, even though they dont come into direct contact with salt water.

I have also had a problem rcently where the engine would not idle, I discovered that if I remove the IAC (idle air control valve) it would idle fine, albeit at higher revs. The smartcraft system also keeps flashing up a check engine message. I am waiting for a new IAC to arrive which I hope will fix this issue, is this a common failure?

 

[ultratiger89]

I am waiting for a new IAC to arrive which I hope will fix this issue, is this a common failure?

very common

 

[Lazy Daze]

very common

Yup. Depending on what part of the ocean you boat, there can be a lot of salt just hanging in the air.

Do you ever spray your engine down with Salt Away? Might not be a bad idea to make this a routine maintenance thing. You can use the one that hooks up to a hose.

 

[Mark V]

The only clamp I've had fail is one of the crimp-on type. (See photo) By coincidence, my boat is in the shop right now waiting on parts for this. As you can see in the photo, about half of the clamp is corroded away in one area. But that was not the whole story.....

It was a persistent dripping leak that kept getting worse, despite a previous trip to the dealer to fix it. I finally found it a couple of outings later, under the exhaust manifold on the starboard side. Using Merc parts list lingo, the bad clamp is on the "3-bib orifice meter". The "3-bib" thing is a plastic fitting with several hoses attached, and it was starting to literally crumble apart under the clamp/hose connection for some reason.

I'm getting it replaced under the Mercruiser warranty. The "3-bib" thing is sold as a hose assembly from Merc, and has a couple of hoses clamped on at the factory with the crimp-on clamps, and a couple of push-on hoses to the Kool fuel box. The mechanic says he's changed them before, and that the new "3-Bib" part will be a new improved version from Mercruiser. (the same mechanic recommends carrying a spare IAC also-he changes a lot of them)

Good thing I caught mine before it let go - that line is an inch or more diameter, on the main sea water line about 1 foot downstream of the sea water pump's outlet- so if it had let go all at once, the engine would have overheated very quickly, not to mention spraying sea water all over the engine compartment.

 

[julians]

The crimp on clamps all seem ok, and seem to be made of thicker stainless steel.

The hose clamps that have failed are the clamps that hold the cooling hose onto the exhaist manifold (but they were double clamped so didnt cause an issue), and the clamp that holds the hose onto the cool fuel unit. This actually failed , and caused an overheat within seconds.

After these failures I decided to go round the engine replacing all the screw on clamps with better quality items, most were ok, but were replaced anyway, a couple just disintegrated when I undid them, these were the other cool fuel clamp, and one of the clamps onto the '3 bib' thing that MArk V mentions above.

My Merc dealer did not have the IAC in stock (I'm in europe, the dealers dont carry all parts), so I altered the throttle linkage slightly to hold the butterfly valve open a little when at idle, these seems to work fine, although for the first start of the day you have to give it a little more revs to get it started, but once warmed up it starts and idles fine.