Carver Owners Forum

How can you determine an engines internal condition when it has been used in saltwater but is raw water cooled and only has a Fresh water Flush system attached. The motors are 25 years old and with only 500 Hrs on them.
I know the instant response is that they Probably have problems, but can they be taken apart to some degree to know for sure? Thanks for any input!
Flott

If they have been flushed after every run as they should be u should be kind a ok. Low hours tell me the boat didn't get run much and could be more of a problem from just sitting around than running in the salt water. Dude it's a crap shoot, u will have to decide if its worth it!

Some times you can remove the thermostat and check the condition of the manifold beneath it. I understand that's an area where deterioration is apt to happen. Obviously the risers and manifolds are of concern. Are there any leaks present at the gasket areas?

The fact that someone installed a raw water flush system indicates a previous owner intended to keep up on the maintenance. Hopefully they stuck with it.
If you have no leaks or external corrosion at the manifolds or risers there is a good chance they have been replaced at least once. They are your "weak point" for raw water cooling systems.
If you own the boat, or are considering purchase, I would run the boat to temp and take several temp readings with an infrared thermometer on various areas of the block and manifolds. If these are fairly close, left to right, front to back, I would then get it out on the water at cruising speed and do the same again after cruising at speed for several minutes, assuming it is running within normal operating temps.
Any hot spots will give you an indication of possible scale build up or corrosion. Not a perfect plan, but should give you an idea of the coolant flow and possible problems needing further investigation.

I agree with Tom. You can also pull the drain plugs on the blocks and exhaust mans and see how much if any internal metal scale comes out. If there's a lot, it may block draining so probe the drain with a zip tie. The scale is a pretty good indication that you're losing metal and even with a flush attachment doesn't always get washed away from some areas in the block. In some areas, if the walls get thin enough, you'll have a major failure. To be safe, one shouldn't expect raw water cooled exhaust manifolds for example to last more than 5-7 years for this reason, so if they're older than that, they're running on borrowed time and if not replaced before they fail, you could be looking at a major engine repair or replacement. Having said all that, the lack of scale doesn't guaranty there's nothing to be worried about.

Flott wrote:Source of the post How can you determine an engines internal condition when it has been used in saltwater but is raw water cooled and only has a Fresh water Flush system attached. The motors are 25 years old and with only 500 Hrs on them.
I know the instant response is that they Probably have problems, but can they be taken apart to some degree to know for sure? Thanks for any input!
Flott

Not sure what you mean when you say , can they be taken apart to some degree, well you sure can, but really why....like has been said a good hard run for a while watching the temps will tell you.....if the cooling system is having problems it will for sure show up after 15 to 30 minutes at cruise under load.

There are some engine flushes that have been talked about lately that may help....do a search on the forum.

The exhaust risers are a good place to start - you can remove the outlet hose easily - 2 screw clamps - and then look inside for corrosion. You can pick up a little borescope/camera from Amazon for less than $20 that will allow you to look around inside. As said above, another spot to look is at the thermostat housing. Here's a link to the camera/borescope - if it does not link - just go to Amazon and search for "endoscope-borescope"

Helpful information. Thanks all!