5.0 glh. Convert from sea water cooling to closed system

bsistrunk77

Recruit
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Jun 6, 2016
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2
I live in South Louisiana. We have access to salt and freshly water. I got a deal on a glastron gt 205. I'd like to be able to run in salt water. I was advised to avoid this unless I convert to a closed system. My question is is it worth it or should I unload it and get a boat set up for it. Looking at parts online it seems it'll cost at least $2000 or so. Any advise would be great.
 

spoilsofwar

Lieutenant Junior Grade
Joined
Jun 29, 2011
Messages
1,124
What year is the boat? It may have a hose flush fitting already installed.
 

bsistrunk77

Recruit
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Jun 6, 2016
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2
2007 glastron gt 205 with 5.0 gl-h volvo penta. It has a flush kit and we use it every time we come in from an outing. I was told. If I continue to run it in salt water I would be replacing the engine in 2-3 years. I've only ran outboards in the past so I am not experienced with in boards. Also we replaced the 5.0 with a 350 Chevy marine longblock motor from gearheads last spring. Fyi
 

spoilsofwar

Lieutenant Junior Grade
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Jun 29, 2011
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1,124
Replacing the manifolds and risers, maybe... Replacing the engine? No.

It's saltwater, not radioactive waste.
 

njlarry

Petty Officer 1st Class
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Sep 13, 2005
Messages
330
I was told by a supplier of fresh water conversion kits that it would do more harm to convert an older engine. Goes against common sense and I still have my doubts about it but they could have just sold it to me.
A fresh water flush is a must. Every two years I would remove and inspect the exhaust risers, replace the gasket and retorque.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
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Jul 23, 2011
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51,243
Converting older motors is difficult because sediment in the block cloggs the heat exchanger.

Use the flush kit, go boating. If you boated every day in salt water and didn't flush, assume 3-5 years for the exhaust manifolds. If you flush, that would be 8-10 years
 
Last edited:

Fishermark

Vice Admiral
Joined
Oct 19, 2003
Messages
5,617
I ONLY boat in salt water and amazingly enough - the engine lasts! Salt water is very corrosive, and yes, you have to stay on top of things and keep them painted and lubricated... but the engine block will last years, if not decades with proper care.
 
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