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Thread: Hot VP engine

  1. #1
    Join Date
    Dec 2007
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    S.W. France
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    Default Hot VP engine

    Did some routine servicing last year on a VP 2030. It was then shifted from La Rochelle to Rochefort for the winter. Couple of days ago, he locks out and goes down the river. About an hour later the engine starts vibrating and the revs go up and down and a bit later overheats. They moor to a buoy and I had a look. Replace cooling water and she runs fine(?) including in gear with a bit of power applied (but not long enough to get very warm?). Suggested they get back to the marina and we have a better look.
    It overheated several times with water loss, but luckily the wind changed and they could sail most of it.

    Yesterday I had a good look. (New) raw water impellor is fine and flow ample from the sea cock. Pulled the exhaust elbow and not blocked. Thermostat opens in a pan of water about the temp listed.
    The only thing I could see was there was no water in the head when I removed the stat.. and the little bleed back to the header tank was blocked.
    So, when they replaced the water, likely it did not expell the air, as the main connection from the header goes to the back of the fresh water pump, low down,and the air in the block could not vent. So likely that expanded and blew the water out of the header tank.
    Probably the original problem was prop fouling with a plastic bag?? which dissapeared? They said the pedestal was vibing quite badly, but by the time I got there, the engine ran smoothly...

    So fresh gaskets and a carefull bleed and coolant top up, followed by a cruising power test against a bollard and constant temp check with a, I-R thermometer.

    Anybody any thoughts on this?

    Fresh water pump problem? That's next if more problems.
    DW

  2. #2
    Join Date
    Nov 2009
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    Home UK Midlands / Boat Croatia
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    19,413

    Default Re: Hot VP engine

    Coolant circulation pumps rarely fail, although they, fairly regularly, leak. However, that's easy to diagnose.

    Some engines have really stubborn air locks and running the engine without checking that all the air locks are out is not uncommon.

    I agree that the vibration was probably something smallish around the prop so it's worth having a dive down to check it's gone. However, I'd be surprised if anyone gunned a vibrating engine hard and long enough to cause it to overheat as the normal response would be to reduce revs rather than increase them.

    Richard

  3. #3
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    Dec 2007
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    Default Re: Hot VP engine

    When they first called, I suggested a dive and they did have 'a feel' round the prop in the murky water. I too am having trouble connecting the vibes with the overheat. But the blocked air vent in the thermostat housing would explain subsequent overheatings.
    I will see what happens tomorrow morn. He wants to set off for Spain and his crew has just arrived....weather window looks good for the crossing to rias.

  4. #4
    Join Date
    Feb 2004
    Location
    Boat: Portsmouth, Us: Stewkley
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    3,007

    Default Re: Hot VP engine

    Worth getting a new thermostat anyway. Ours failed years ago. As you did I tested in a pan of water and it opened seemingly ok. But popping a new thermostat in the same pan it was clearly only opening only a third compared to the new one. PITA as it would only overheat when loaded.

    ISTR the gasket cost more than the thermostat!

    Overheating problems are a pain. Hard to load the engine. And they take ages to overheat. I think that's when I bought a cheapo IR thermometer from Maplin. Very useful as it takes away the guessing.

  5. #5
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    Dec 2007
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    Default Re: Hot VP engine

    Getting bits in a hurry here is not so easy.
    Put the bits back and ran it for 40 mins against the ropes. Temps remained constant after warm up, so off they go to Spain.
    Used an I-R thermometer to check on the block, head, stat housing, elbow and assorted pipes. Very useful tool, mine from B&Q.

  6. #6
    Join Date
    Sep 2013
    Posts
    251

    Default Re: Hot VP engine

    As a matter of interest what temperatures did you find with the IR thermometer? On a raw water cooled MD11C working hard I get 75-85 C on the cylinders and 45-55 C on the exhaust elbow. I suspect cooling flow around the cylinders is not as good as it could be but I am fairly sanguine about their temperatures as long as they stay constant.

  7. #7
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    Dec 2007
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    Default Re: Hot VP engine

    Not far off.
    Block was 75
    Head 72
    Stat housing 78/82
    Elbow 45

  8. #8
    Join Date
    Sep 2013
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    251

    Default Re: Hot VP engine

    Thanks, reassuring...

  9. #9
    Join Date
    May 2007
    Posts
    16

    Default Re: Hot VP engine

    Had this on my current 2003t and previous VP engine. The little bleed nipple back to the header tank was at fault both times! Flush the engine with a rad flush to clear the rubbish out as. much as possible. I also bored mine out slightly as its the size of a pin! Hope this helps.
    Paul

  10. #10
    Join Date
    Dec 2007
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    Default Re: Hot VP engine

    Interesting, Paul
    This was actually a 2003, not a 2030 (finger trouble..), so the same.

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