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  1. #1

    Default Under Hood Temps

    1995 Mercruiser 350 Tournament Ski Direct Drive in a 1995 Ski Sanger DLX 20 tournament tow boat. Anybody have a rough idea of the top temp under the engine cover? (I don't have any automotive/scientific measuring devices. Maybe I could use my instant-read meat thermometer?) Not talking about engine operating temp, but the space around the engine and bilge. I want to install a fuel shut off in the fuel line that runs on the starboard side of the boat, and I want to make sure the valve I install will operate safely in the temp in there. Please don't overthink this. I have a reason to do this and want to do it safely. If you can't come up with a number, that's OK. If you can reference a part you think is right for the job, even better. Knowledge helps, not opinion. Let's not get into a 40-post discussion. Many thanks for your help.

  2. #2

    Default Re: Under Hood Temps

    Most run blower 80-95% of time.

  3. #3
    Join Date
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    Default Re: Under Hood Temps

    Go to home depot and purchase a infrared temp gun ~$25.00

    figure it out for yourself.

    Just a thought that shouldn't provoke a 40 post discussion,

    If it were too hot, it would melt the inner parts of the engine cover............

    The bilge is very cool compared to manifold height as Heat rises not to mention for in Inboard, there should be water present from the drip of the shaft seal......

    Why not install this shut off valve in the soft line feeding the water separating filter? If it has NPT threaded fittings you could adapt it to the input threaded fitting on the water separation filter mount.

    This should rap up your post in three (3) posts.

    Will that work for you?
    Jack
    Mass.

  4. #4
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    Default Re: Under Hood Temps

    Believe it or not there are actually regulations written for this. If the engine cover is the original, then it should be providing adequate ventilation to keep temps only slightly above ambient. In a marine engine, the water cooling is very efficient at removing heat. So much so that the thermostats are at what would be ridiculously low set point for an automobile in order to keep the combustion efficiency high. Temp under the cover will spike when the engine is shut off and the cooling water stops flowing but at that point there's no more heat being generated so the spike isn't that big of a deal. Your manifolds should not be any hotter than the thermostat setting.
    For the purposes of fire control, most automatic fire suppression systems will trigger at 175 degrees F.
    Practicing the ancient art of ren-ching

  5. #5
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    Default Re: Under Hood Temps

    Quote Originally Posted by o2batsea View Post
    Believe it or not there are actually regulations written for this. If the engine cover is the original, then it should be providing adequate ventilation to keep temps only slightly above ambient. In a marine engine, the water cooling is very efficient at removing heat. So much so that the thermostats are at what would be ridiculously low set point for an automobile in order to keep the combustion efficiency high. Temp under the cover will spike when the engine is shut off and the cooling water stops flowing but at that point there's no more heat being generated so the spike isn't that big of a deal. Your manifolds should not be any hotter than the thermostat setting.
    For the purposes of fire control, most automatic fire suppression systems will trigger at 175 degrees F.
    Inboard Ski boats are a bit different design, Engine in middle of boat under a NON vented cover.

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    Jack
    Mass.

  6. #6
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    Default Re: Under Hood Temps

    Personally, I never shut my bilge blowers off. Too easy to forget to turn them back on.

    Jeff

  7. #7
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    Default Re: Under Hood Temps

    The design point for engine box air temp is 150 deg F for the modern fuel injected engines....any fuel valve should easily handle that temp (not that it would see it down on the sringers....as far as a specific part, do a search on <moeller brass fuel shutoff valve> for a specific example. sealed ball valves with a non-corroding body would be suitable equivalents, with the proper terminations...

  8. #8
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    Default Re: Under Hood Temps

    approved fuel shut off valves are rated to withstand a fire... you are overthinking this...
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280

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