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1997 Carver 355 Aft Cabin - engine vaporlock

Discussion in 'Carver Yacht' started by wmcdan, Apr 30, 2012.

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  1. wmcdan

    wmcdan New Member

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    I have a 1997 Carver 355 Aft Cabin with twin Mercruiser 457 engines. I'm am not a mechanic by any means, but I've been told the problem I have is the engine is vaporlocking. I always watch the temp gauges and they never go above 180. I always leave the blowers on when the engines and generator are running, and I leave the blowers on when I stop the engines after running for a while. There is a lot of heat buildup in the engine compartment while running. If I stay stopped for a while, the fuel in the line to the carburator evaporates and I have to bleed the line of air to get the fuel back up to start the engine. Any ideas what might be causing this ?
  2. sam356

    sam356 Member

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  3. sam356

    sam356 Member

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    Make sure all your vent to the bildge are clear nothing is blocking it. Also if you can turn a vent cover so it force air into your bilge when your movig it might help. If you have old fuel run at a low rpm until your tanks are almost empty than put new fuel in it.
  4. wmcdan

    wmcdan New Member

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    Thank you, Sam. I have wondered about the vents on the side of the boat. On both sides the vents are turned where the fins point toward the aft of the boat. Do you know if this is the way they were installed from the factory or should one vent be turned where the fins are facing forward to help catch the air and force it into the engine compartment ?
  5. sam356

    sam356 Member

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    The way you have them now is factory but I had a sea ray sedan were I turned the front vent so it will force the air in the bilge and engines ran better. I would try turning them around nd see if it makes a difference also if you don,t have one get your self one of those heat guns you can pick one up at harbor freight cheap and see if your temp goes down.
  6. wmcdan

    wmcdan New Member

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    I'm not sure what a "heat gun" is ?
  7. sam356

    sam356 Member

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  8. tommyfmu

    tommyfmu Member

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    I'd suggest having your carbs, fuel lines and fuel pumps checked out. I have Holley 4 bbl and had them rebuilt last year after having symptoms that mirror vapor lock, but it wasn't.
  9. Ormond Bert54

    Ormond Bert54 Senior Member

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    Also likely an Ethanol problem ... use Stabilizer with every tankful. Probably need to have the carbs rebuilt, change the fuel filters and made sure there is nothing clogging the one way valves on the top of the fuel tank.
  10. Capt J

    Capt J Senior Member

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    Do not turn the engine room vents around on the side of the hull, in rough seas it could and probably would flood the engine room.

    You can check the vents for the fuel tank, simply by opening the fuel fills on the tank and see if there's a vaccuum after running (before starting them again) then see if they start ok after you do this.

    Next, have you changed the fuel filters recently? If not, I would definately do this. Then have the carberators/fuel pumps checked. You can put a fuel pressure gauge on the fuel line and see if you're making enough pressure as well.
  11. wmcdan

    wmcdan New Member

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    Thanks for the replies. I have changed the fuel filters. I do use the fuel stabilizer. I guess the next step is checking the carb. and fuel pump. I don't think I really have to worry about flooding the engine room since I'm not in rough seas.... just the TN river and lakes so far, but one can dream :)
  12. Capt J

    Capt J Senior Member

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    Well, you also don't want the vents foward because you could force so much air into the engine room, causing engine room gases to go into the living area's.......
  13. True North

    True North New Member

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    I have the same year/model and the same problem with my Crusader 454XL engines. They are fuel injected (Throttle Body Injection) and I've learned that the blowers are the key. My vapor lock issue only happens when its over 80 degrees outside, and is especially prominent when I'm running my generator to power the air conditioning. Even if the engines haven't been run for most of the day, the generator will cause my engines to vapor lock. I can clear the vapor lock as long as the blowers have been running well after, and well before engine start up. By that, I mean a solid 30 minutes. I realize you posted this 5 years ago, but if you're still having the issue, I hope this helps. I'm considering adding another blower to mitigate the issue.

    Best of luck
  14. Capt J

    Capt J Senior Member

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    If your generator is running on a gas boat, the blowers should be on the entire time the generator is running, even if the engines are not.