freshwater cooling

[The W.A.V.E.]

Sarbog asked a question in his bottom paint thread regarding freshwater cooling. I have 7.4's in a 1999 340 with 350 hours on them. It is kept in a wetslip in warm Gulf waters around Clearwater Florida. My question is, does it make sense to put freshwater cooling on or not. I have seen different types of units like a complete system cooling and freshwater cooling for the engine only. Any ideas or opinions would be appreciated.

 

[67vetteal]

Sarbog asked a question in his bottom paint thread regarding freshwater cooling. I have 7.4's in a 1999 340 with 350 hours on them. It is kept in a wetslip in warm Gulf waters around Clearwater Florida. My question is, does it make sense to put freshwater cooling on or not. I have seen different types of units like a complete system cooling and freshwater cooling for the engine only. Any ideas or opinions would be appreciated.

Fresh water flushing after use is recommended on all types of Marine Service components. So, why wouldn't a complete Fresh Water cooled system benefit your engines? You limit Salt Water incursion to a great degree. Al W.

 

[The W.A.V.E.]

I agree that a fresh water rinse helps, I guess my question is when is it not worth the investment. The engines are not rinsed after use now as it is not a common practice for inboards here in Florida. I figure it is a $2.5k to $3.5k investment, and would it really extend the life of the engines? And if it does how much longer? I just dont know if putting the money into this is worth it, maybe its better spent on something else,

 

[Sundancer]

Usually after about 150 hours of salt water use it's not recommended. I believe it has something to do with what happens when the salt deposits/salt water build up mixes with the ethylene glycol. I'm not entirely sure I have this right, but it forms kind of a sludge or jello like substance that inhibits cooling. The other half of the thought was to save the cost and apply it toward the new engines or add FWC when you replace the engines, if you own the boat that long.

I think there used to be a mark around 240 hours when it wasn't recommended in freshwater, but that one doesn't make much sense to me. It seems like it could still be beneficial at that point? I had a 250 DA with 220 hours on it when we bought it. I looked into having it done around the 300 mark. We boat in freshwater and the consensus was not to bother. I wish I had it on our 300 DA, but the hours are approaching 700.

 

[Dirtguy]

It IS worth the investment. That's why it's an option for upgrade. It does require more parts and slightly more attention, but the rewards are many. Better heat control, possibly better mileage, NO corrosion again, and peace of mind. Many kits available for a reasonable price. Save your investment. To go closed cooling is about $1000 per engine. Kits are available at most online suppliers and with the economy, they'll likely make a deal.

My 260 7.4L WAS raw water cooled and I asked some experts and never looked back. Now, I just check the coolant and motor away. I collected the parts and assembled my own for about $475 total. Now I have a better pump and more friendly components in more serviceable locations.

dg

 

[The W.A.V.E.]

Good info guys, however differing opinions, is there anyone else out ther that could weigh in on this subject, so far its one for and one against. Thanks for the replies.

 

[Sundancer]

I'd go look at some other websites. Specifically those that sell the kits. I think they'll set you straight, but I'm sure others will chime in with real experience!

The truth is out there......

 

[tobnpr]

My $.02 based on experience. Had a RWC 350 in my Chris-Craft for 8 years, same geographic area as you. I had to replace the heads due to a failed riser and the interior of the block showed very little corrosion. I routinely flushed the engines- which accomplishes the same thing.

If I were buying new engines, FWC without a doubt. But since they're already nine years old, I'd install a flushing attachment and flush after use. IMO the block itself is pretty tough and not affected much by saltwater- it's the manifolds and risers that suffer due to the extreme heat and the saltwater mixing with the exhaust.

The boat doesn't see much use- 350 hours in nine years- so flushing after use would leave freshwater in the engine for the long periods she sits. Forget "investing" in FWC on those engines and just flush 'em after use.

 

[Nehalennia]

Usually after about 150 hours of salt water use it's not recommended. I believe it has something to do with what happens when the salt deposits/salt water build up mixes with the ethylene glycol. I'm not entirely sure I have this right, but it forms kind of a sludge or jello like substance that inhibits cooling. The other half of the thought was to save the cost and apply it toward the new engines or add FWC when you replace the engines, if you own the boat that long.

I think there used to be a mark around 240 hours when it wasn't recommended in freshwater, but that one doesn't make much sense to me. It seems like it could still be beneficial at that point? I had a 250 DA with 220 hours on it when we bought it. I looked into having it done around the 300 mark. We boat in freshwater and the consensus was not to bother. I wish I had it on our 300 DA, but the hours are approaching 700.

I've heard that it's 100 hours but you are correct. If you invest the $$$ now after this long the "investment" won't yield the protection that it would if it's done when new. It may be best to keep a good regimine of flushing then add FWC if you keep the boat long enough to repower. The downside is that you may need to repower to sell the boat or your value will be diminished because you have RWCooled engines in a saltwater boat.

I bought my boat(from Freshwater owner) with 94 hrs. It had been used in saltwater for a total of 10-12 hours. I added FWC, because it fit the "rule-less than 100 HRs)

Good luck

 

[The W.A.V.E.]

Thanks guys, I think a flushing kit is the way to go, and with the savings, I think I'll get that 20hp outboard for my dink I've been wanting. Thanks again for the opinions.

 

[Dirtguy]

If you keep up on your zincs and flush you can save some money now, but you'll re-invest it later. Does the Mercathode system come into play here with the engine corrosion too?

As far as referring to the actual product sites for a opinion. I think that giving you a differing opinion, other than buying them, isn't in their best interest. In other words, don't expect an honest opinion on whether to not to make the transition..

If you know a boat shop owner, or better yet, a marine technician, who won't profit from you, ask him.

dg