Question: A boat I just looked at has me a bit concerned, because I really like most things about it and I'm thinking of putting down a deposit.

Here's a recipe for trouble: The insulation is in contact with the turbo below it, and the  battery isolator is mounted too close to the turbo and exhaust system.

Here's a recipe for trouble: The insulation is in contact with the turbo below it, and the battery isolator is mounted too close to the turbo and exhaust system.



The photo shows an electrical component with red battery cables connected to it. Directly below this electrical box you can see a turbocharger for the engine. I own a car with a turbocharger and I know that on long runs the turbo gets really hot under the hood. On this boat the turbo is actually in contact with the foam sound insulation on the engine box walls, and I think it may be too close to the electrical component those red battery cables are attached to. Any advice on this would be appreciated.

Answer: Looking at the photo you sent in I have to agree that what you see is, at the least, a premature component failure waiting to happen. It appears that the electrical device is a diode-type battery isolator, which will get quite warm all on its own when the engine is running and the alternator on the engine is pumping power through it. Add the extreme heat the turbocharger will be radiating, and you most certainly do have a recipe for early component failure.

As for the foam insulation in contact with the turbo, I can’t imagine what the engine installer was thinking.

Two things need to happen here. First the battery isolator needs to get repositioned as far away as possible from the turbocharger and any other exhaust components on the engine. ABYC Standards dictate that electrical wiring be separated from dry exhaust sections by at least nine inches.

Second, a section of that foam insulation needs to be removed near the turbo charger housing to ensure that there's no direct contact between the foam and the body of the turbo. It’s hard to say exactly how much foam should be removed without actually taking some temperature readings. This is a good place to use an infrared heat sensing thermometer with a laser pointer to actually measure the temperature all around the turbo housing with the engine running. The makers of the popular Soundown engine room insulation kits say it this way: “Remember that the foam is rated as fire retardant, NOT fire proof.”

I couldn’t find a specification that actually identifies an ignition temperature or melting point for Soundown specifically. ABYC’s exhaust system standard P-1, however, uses a temperature of 200 degrees F as a maximum temperature allowed before thermally protective guards or shields are required around exhaust system components.

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