Cobaltchat.com

In 2011, I brought a fresh water only 2003 Cobalt Model 226 w 5.7 liter DP to the salt water environment. For a couple of years, the boat was kept in the water at the dock until we put in a boat lift about 2015. The engine was a raw water design but had the fresh water flush with it. From the beginning, I treated the boat similar to a Jet Ski: we always put the boat on a fresh water flush 10 minutes when returning to dock. We would run the boat on city water before shutting her down. We continued the practice religiously even after the boat was on the lift.

The recommendation in salt varies locally, but some variation of replacing the impeller after two years and exhaust manifolds after six years. We went along with the recommendation on the impellers but would say they always looked fine to the eye. The boat never had any issues with manifolds and we sold the boat to a brackish environment last spring and it continues to run strong for the new owner.

When asking professional opinions on the "effectiveness" of fresh water flushing, there is little offered beyond "it can't hurt".

Fast forward to a new 2020 R-5 with the Volvo 5.7 DP but a "salt water package" including closed cooling. At this point we are still doing the fresh water flush when returning to the lift (old habits are hard to break), but I am assuming that we are only putting the fresh water flush through the heat exchanger and the raw water pump. My understanding. I also notice the outdrive comes with what looks like a water flush/hose connection but I am unsure as to what I should consider with this. The dealer said it is simply a flush for the outdrive and flushing is to a non running engine.

Anyone with experience or thoughts on this outdrive flush feature/function?

In closing, I like the idea of the outboard engines in salt water environments but not always easy to get a great boat or boat design, depending upon the boat builder.
Herb

2020 R-7

First, not a professional; just an informed tinkerer.

I think I would keep flushing. First, it seemed to work well for you in the past. Even with closed loop cooling, raw water is still flowing through numerous components beyond the raw water pump and heat exchanger: power steering cooler, fuel pump, numerous channels and hoses from the outdrive to the raw water pump, exhaust elbows, bellows.

I thought the flush ports on the outdrive/engine bay could be used interchangeably, but please dont take my word for it!

Probably not a 5.7 in the 2020?

Greenhut:
Thanks for the thoughts on this.
Can any others confirm: Is the outboard engine flush
hose connection merely "inline" with the fresh water flush port
in the engine compartment and either of them can be used
to flush a running Volvo engine?

Herb

If it’s a flush port,use it. You can’t overflush, but you can underflush. Any part of your VP that touches saltwater is an expensive one. Prolong its usefulness so you have more cash for fuel. More fuel = More smiles

On the new gen VP 5.3L (6.2L too) the two ports can be used in the same manner. Depends on your preference and which is more convenient. Both need to be running water before turning over the engine. It might flow without the engine on but I would think the raw water pump impeller would restrict the flow quite a bit. Since the internals are closed cool you don't need to run it very long like the raw cooled. The thermostat does not impact the flow. Raw water flows through the pump, heat exchanger, exhaust manifolds and risers and then through the exhaust portion of the outdrive. VP also adds a set of anodes located on the exhaust manifolds for additional protection. It is the best setup for saltwater protection, way better than any outboard offering. Aside from of annual maintenance I never understood the logic that outboards are a better option in saltwater.

On my old boat that I used in salt water, I also added the Volvo Neutra salt system. I would engage it right before I pulled it out of the water and again after flushing to keep the agent in the block and manifolds after I shut down.