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smokediver
03-13-2011, 10:31 AM
say a person has a 496 fresh water cooled .. runs the boat about 25 hours a year for 5 years and the only time it is flushed is when it is winterized .. doest the raw water cool the fuel cooler , manifolds , etc ? wonder if there is going to be problems ... i found a boat but am a little worried .. thanks in advance .

joseph m. hahnl
03-13-2011, 02:49 PM
say a person has a 496 fresh water cooled .. runs the boat about 25 hours a year for 5 years and the only time it is flushed is when it is winterized .. doest the raw water cool the fuel cooler , manifolds , etc ? wonder if there is going to be problems ... i found a boat but am a little worried .. thanks in advance .

When you say fresh water cooled you mean closed cooling or raw water?

The biggest area for corrosion, on either, is the riser. In either system that is where salt water comes out of the system. Just by pulling the rubber exhaust hose off, can tell you a lot about the condition of the rest of the motor. The amount of usage doesn't really say much, If the motor was filled with sea water for prolonged periods of time. There could be extensive blockage. Another area you can check with ease is the thermostat housing. By pulling one of the by pass hoses at the thermostat housing.You can see if the port has blockage.


The Motor in my Minx Had sea water in it for five years. The only things I could not salvage where the heads and thermostat housings. Although, there was extensive blockage in the intake manifold, I was able to clear that out. The Risers where perfect.

So I came to the conclusion that a dry engine will fair better than a wet engine.

smokediver
03-13-2011, 03:13 PM
mag ho engine .. closed cooling ..

Tidbart
03-13-2011, 06:09 PM
Hey John,

I take it the beak is gone. :)

Assume it will need a lot of work and price accordingly.:tongue:

Also, remember the 22 with 502 that I mentioned, in Orlando.

Good luck with your search.

B

smokediver
03-13-2011, 07:24 PM
yea bob , its gone .. sold a few weeks ago .. I kinda want the newer mag ho set up .. the boat was listed on here before winter and i talked to the guy about it .. seems like a good deal , just a little leary that it wasnt flushed .. lift kept 5 years old 120 hours .. winterized yearly .. he said he has had no issues at all with the boat .. price is right but am thinking the risers and manifolds will need replacing at a minimum ..

joseph m. hahnl
03-15-2011, 04:46 PM
yea bob , its gone .. sold a few weeks ago .. I kinda want the newer mag ho set up .. the boat was listed on here before winter and i talked to the guy about it .. seems like a good deal , just a little leary that it wasnt flushed .. lift kept 5 years old 120 hours .. winterized yearly .. he said he has had no issues at all with the boat .. price is right but am thinking the risers and manifolds will need replacing at a minimum ..

If it's a full cooler the exhaust manifolds never see raw water. Only the risers are wetted by raw water. The 1/2 cooler will wet the exhaust manifolds with the risers.

smokediver
03-15-2011, 08:38 PM
If it's a full cooler the exhaust manifolds never see raw water. Only the risers are wetted by raw water. The 1/2 cooler will wet the exhaust manifolds with the risers.
Along with the heat exchanger , power steering cooler , oil cooler , cool fuel cooler ? just trying to get an idea what might need to be replaced is all ..

MOP
03-15-2011, 10:00 PM
Ask him to let you pull the cooler caps, it can look kind of gunky and still be just fine. Look to see if the "Zink" appears to have been kept up with. Hunch it will be Ok!

silverghost
03-15-2011, 10:12 PM
Most of these coolers & heat exchangers last a very long time indeed as they are made of bronze.

As mentioned above sacraficial zinc pencil anodes are used to protect some of the coolers & most heat exchangers .
I have had oil coolers that have lasted 20 + years ! Heat exchangers that have also lasted as long, or much much longer.
Heat exchangers need their inside tubes cleaned at times with a long rifle bore cleaning brush.

I suspect that the only thing that you will really have to worry about are your manifolds & exhaust riser elbows in salt water use !
Iron elbow risers & manifolds usually last about five years when used in salt water.
I do 99% of my boating in salt water ; and have done so all my life !
Frest Water Cooling closed heat exchanger systems are a must in salt water !

My current boat is 15 years old with a fresh water cooling 1/2 system.
Exhaust manifolds & risers are raw-saltwater coole cast iron.
I have 1500 hours on my 454 Chevy engine and it's almost like new !
I am on my third set of iron exhaust manifolds and riser elbows !
I am now due for a new ehaust manifold & riset set !

Buy the boat~~~replace the manifolds & risers, + replace any zinc anodes & enjoy your summer boating with your new boat !

mrfixxall
03-15-2011, 10:30 PM
pull the water supply hoses off the cooler and have a look inside,also take the hoses off going to the risers,some of the 496 ho's had alunimum manifolds and some were cast iron but the risers were all painted stainless steel so those should be ok.

silverghost
03-15-2011, 10:37 PM
Most aluminum exhaust manifolds do not hold up vert well, or very long in salt water use.
Iron manifolds last much longer;~~~about 5-7 years if not flushed on a regular basis after each & ever use !
Stainless steel is best .
But it too~~~ has some possible cracking issues.

Stainless Steel exhaust riser elbows are the best in many ways !

joseph m. hahnl
03-16-2011, 05:50 PM
Most aluminum exhaust manifolds do not hold up vert well, or very long in salt water use.
Iron manifolds last much longer;~~~about 5-7 years if not flushed on a regular basis after each & ever use !
Stainless steel is best .
But it too~~~ has some possible cracking issues.

Stainless Steel exhaust riser elbows are the best in many ways !

That's why I chose to keep mine a full cooler. Runs a bit hotter than a 1/2, but you never have to worry about the manifold corroding.http://www.donzi.net/forums/attachment.php?attachmentid=45488&d=1241133220