Salt Water I/O info please

[tonyjvan]

Can't find an answer to this by searching.. probably because it's a really dumb question.<br /><br />I'm looking at boats with I/O drives to be used in salt water. I prefer a fresh water cooled engine because that's what my inboard had. <br /><br />But a lot of I/O boats I'm looking at have raw water cooled engines. Am I missing something? I assume fresh water cooled is preferable for salt water. Is there a way to flush the block at the end of the day like an outboard?<br /><br />And... can a raw water cooled engine be converted eaisly to FWC?<br /><br />Any advice from you experienced pros is very much appreciated. <br /><br />Tks Tony

 

[Boomyal]

Re: Salt Water I/O info please

Yes, they can and you must flush a raw water cooled motor after use in saltwater. The reason that most of the I/O's you're looking at are raw water cooled is a simple matter of cost, initially that is.<br /><br />I presume that closed cooling kits are available for most I/O's produced in the last couple of decades. They usually cost upwards of $500.00 and can be had in 'engine only' or with some motors, both the engines and partial exhaust manifold.<br /><br />Another advantage of a closed cooling system, besides the obvious, is that you can run a hotter thermostat for better combustion efficiency. Engines run in saltwater need thermostats as low as 140 deg(max 160) or the salt will plate out inside the engine. These temperatures are considerably less than desireable for efficiency.<br /><br />Additionally, a closed cooling system is easier on the motor due to a reduction of expansion and contraction from cold outside water entering the engine as the thermostat opens and closes.

 

[achris]

Re: Salt Water I/O info please

Tony,<br /><br />Didn't say what engine you're looking at. Where I am we only have salt water. I've worked on V8s that are 20 years old and have no problems with salt. They flush out at the end of the day the same as an outboard. Just put the flushers on and fire it up. Let it run at IDLE for a few minutes and she's done. I have a V6 and put closed cooling on it from day one, because the head castings are thinner than on the V8s. All of what Boomyal said about running hotter is right though, more efficient. One of the service reps here HATES closed cooling, he says it involves too many more things that can go wrong. Another downside of closed cooling is the need to have the heat exchanger cleaned out every couple of years. I guess it's six of one and half a dozen of the other.<br /><br />Chris..........

 

[Bondo]

Re: Salt Water I/O info please

Keep looking till you find a Closed system......<br />Or do the conversion.......<br />It's money in the bank, for the Long Haul........

 

[Lou C]

Re: Salt Water I/O info please

Be aware that if it has been run in salt for longer that about 100 hrs or so, supposedly you cannot add closed cooling because of the rust and salt already in the engine, which will clog the heat exchanger and cause chronic overheating.

 

[tonyjvan]

Re: Salt Water I/O info please

Thanks for the very useful replies.<br /><br />I was looking at a Mercruiser w/six cyl chev block. The enging has about 1500 hrs and I would probably have a rebuild or short block done.<br /><br />At that time, I could (if I buy it) think about the FWC conversion.<br /><br />Again, thanks!<br /><br />Tony

 

[ICC]

Re: Salt Water I/O info please

On the same subject of salt water V8s, what are the common failure items to be concerned about ? I recently bought a boat with a 5.0 Mercruiser that I suspect probably has 150 hours or so and is a 1989. Engine runs good although I have not had the boat in the water yet and was concerned about any salt water issues from prior use. Any thing to check for tell tale signs of engine failure would behelpful such as the common corrosion points.<br /><br />Thanks<br />Mike

 

[achris]

Re: Salt Water I/O info please

ICC<br /><br />3 things to check. Elbows, elbows and elbows... At 5 years old I would be pulling them off and checking them. Easiest way to check them it to turn them upside down and with a big flat screwdriver, hit on the inside of the top of the elbow. If the driver goes through, get a new one (two). What really kills them is lack of use. Just sitting there corroding quietly away to themselves. <br /><br />Chris..........

 

[Kiwi Phil]

Re: Salt Water I/O info please

achris60.<br />I am pretty new to I/O.<br />My 5.0L Mercruiser (1984) sits in salt water all the time. It has S/S risers. I have put on new manifolds and been told to change them every 4-5yrs.<br />I'm Brisbane area.<br />There is talk of flushing etc which I can't do.<br />Have you any advice.<br />Cheers<br />Phillip

 

[achris]

Re: Salt Water I/O info please

Phillip,<br /><br />S/S elbows are a good start. The manifold should last a bit longer than 4-5 years. I would have expected about 8 years. If they remain filled with water then the oxygen can't get to the metal and it can't rust (as quickly). If you're happy to get wet at the end of each trip out (after all, it is Queensland ) you could slip over the side and put flusher on it. If you could be bothered. <br /><br />Chris........

 

[Kiwi Phil]

Re: Salt Water I/O info please

Nope!!! I will leave it just as it is and wear the cost.<br />Thanks<br />Cheers<br />Phillip

 

[RatFish]

Re: Salt Water I/O info please

I heard some people on another board praise the MST Guardian for flushing their I/O's. Since I don't have any first hand experience, I don't know if it's any good. It's kind of expensive at $280!

 

[cobra 3.0]

Re: Salt Water I/O info please

...then just buy some muffs.<br /><br /> http://www.iboats.com/mall/index.cgi?prod_id=40372&current_category=flush&cart_id=553507462

 

[tystick]

Re: Salt Water I/O info please

sorry for rookie question:<br />are elbows & s/s risers the same? where are they located and how easy to remove and check and/or clean? <br />Is there any other way to remove internal rust build-up if already existing. flushing will only prevent future rust?

 

[Fishermark]

Re: Salt Water I/O info please

Elbows and s/s (stainless steel) risers are the same thing, just made of different material. They sit on top of the exhaust manifold and look like an elbow (hence the name ). I don't have experience with the stainless ones.<br /><br />They are easy to remove, as long as the bolts are not seized up. I know there are differences of opinion here, but I have had success with removing them, and pouring some Muratic acid in the passages and cleaning them up and reusing them. (USING COMMON SENSE PRECAUTIONS WITH THE FUMES, ETC! ) This doesn't work if they are badly corroded or plugged up, but it does prolong their useful life.

 

[achris]

Re: Salt Water I/O info please

The risk with elbows (risers, heat exchangers, funny things that live on the top/at the end of manifolds) is that this is the most common place water enters the engine. If in doubt, chuck it out. Why risk several thousands (potentially) of dollars damage for a couple of hundred (and peace of mind). The best way I have found to check elbows (apart from the float test) it to turn them upside down and with a big flat screwdriver, hit on the inside of the top of the elbow. If the driver goes through, get a new one (two). Cleaning with Muratic acid (toilet cleaner) is something I have heard about but haven't tried. I run S/S