84 50hp evinrde help

Discussion in 'Outboards' started by clay467, Jul 24, 2015.

  1. clay467
    Joined: Jul 2015
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    Location: florida

    clay467 New Member

    ok i have an 84 evinrde 50hp.the engine starts right up and runs with the warmup lever up.but wont idle when the lever is down. but the weird thing is it idles just fine with the fuel line disconnected. as soon as you hook the fuel line up the engine stalls. i rebuilt the carbs to see if this would fix the problem. also have a new fuel tank. but it still runs with the line off n stalls when you connect the fuel line any thoughts on this
     
  2. Mr Efficiency
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    Mr Efficiency Senior Member

    Might be sucking air from the fuel line/fittings.
     
  3. Capt Drake
    Joined: May 2015
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    Capt Drake Junior Member

    If you have already overhauled carbs, check adjustment needles and fuel diaphragm. It may not be able to maintain flow when it has fuel hose on.
     
  4. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    When you rebuilt the carbs, who did you clean the orifices and passages? Usually on an engine of that vintage, you're best off just replacing all the rubber elements. Any diaphragms, hoses, gaskets, etc., because you know they're not going to be seating, fitting or holding the way they should. You problem sounds like a pump issue, which has just enough volume to move a small column of fuel, but not a larger one, in the delivery system.
     
  5. Mr Efficiency
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    Mr Efficiency Senior Member

    If it runs satisfactorily with a gravity fuel feed, (elevate a portable tank) chances are the fuel pump is the culprit. ALthough I do vaguely remember having a similar problem once, and there was an issue with the snap-on fuel connection being faulty.
     
  6. SukiSolo
    Joined: Dec 2012
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    SukiSolo Senior Member

    Along with PAR's suggestions of rubber perishing etc, and the fuel pump, one other thing can happen. If you have hollow polymer floats, (main fuel chamber) they may become porous and too heavy, even without necessarily containing fuel. This then puts the float level at the wrong position. Even half a gram can make quite a difference.....;) on a sensitive carb.
     
  7. clay467
    Joined: Jul 2015
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    clay467 New Member

    upddate

    ok changed the connector on the fuel tank. got motor to idle. now i have to run her with the manual choke at half way. motor runs great in this position i know there is still a problem having to run it like this. any suggestions
     
  8. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Yep, if the choke has to be pushed in to run, you've got partially plugged passages, orifices, etc. Pull it apart and using the shop manual, clean and bring the carbs to specs. Cleaning is a lot more than spraying some carb cleaner all around and hoping it soak in. The passages (all) and orifices need to be physically scrubbed of varnish, debris and residue. If the rebuild was done right last time, it's probable you have deteriorating fuel lines, which might look fine on the outside, but are shedding bits of rubber inside. This means replace all rubber lines, the primer bulb, etc., just so you know you got it. Otherwise you'll be playing the hit or miss game, which isn't much fun. On a boat of that age, it always best just to assume the rubber is original. Level the playing field and move onto the next things on the list you'll need to address.
     
  9. CDK
    Joined: Aug 2007
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    CDK retired engineer

    My son had a Johnson 50VRO with the exact same problem. An endless story of replacing parts, cleaning and messing with the adjustment screws, all to no avail.
    Last year, in a desperate moment he bought an overly expensive spray can "Johnson carb cleaner" and followed the instructions. An hour later the engine ran idle like a new one.

    It seems there are passages and orifices that you cannot clean in any other way. The can contains an unhealthy mixture of acetone, toluene and xylene, but it does the job well.
     
  10. clay467
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    Location: florida

    clay467 New Member

    thanks for the replies

    thanks for all your replies.i did take the carbs apart .took out the orfaces.cleaned them.and checked the float levels.i guess the next step will be to replace the rubber fuel lines and then go from there.thanks again
     

  11. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    The first generation of Honda 4 strokes had similar issues. Any dirt at all and they ran like crap. The cleaning process has to be complete. I've used my own mix of carb clear for years, simply because the retail spray versions have to comply with too many requirements for public consumption, that they're less than effective.
     
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