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  1. #1
    Cadet
    Join Date
    Apr 2008
    Location
    Copenhagen
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    4

    Default Yamaha V4 115 HP 2 stroke - Cold starting problem!!!???

    Hello everyone.

    I am having big problems with starting my Yamaha V4 115 HP 2 stroke engine when cold. When its hot it starts immediately.
    Ive cleaned the carbs several times thoroughly and adjusted the pilot screws according to the instruction book. The Solenoid Choker function is working sufficient and it closes the Choker throttle as it is supposed to. But somehow, it sems like it doesnt provide enough fuel when the engine is cold. I need to use compressed start gas to get it running every time. Then it starts almost emmediately and runs normally after a few seconds.

    Ive also tried to start without choke, with a little throttle opening and a lot of throttle opening - but same result. It cranks one stroke and the starter is disabled, without starting the engine. Sparkplugs are new.

    Try to take a look at this video which is an attempt to start it normally, with the choker activated.
    This is after trying a looong time and suddently it starts.

    Yamaha V4 115HP starting problem - Whats wrong ? - YouTube


    Its been like this for all the time Ive had it.

    Any ideas for carb adjustment ? What about the pilot / air screws, any experiences with adjustment ?

    Thanks in advance.

    Michael.

  2. #2

    Default Re: Yamaha V4 115 HP 2 stroke - Cold starting problem!!!???

    Michael.

    I have the same outboard and I am having the exact same problem. I started a thread to see if anyone could help me and just came across yours. I noticed that no one responded to yours. Did you ever find out what the problem was? I would appreciate the help. I have replaced the Bulb but it hasn't changed. I was thinking that maybe the fuel pump is weak and i should rebuild the diaphragm. Anyways any advice would help.

    Chavi.

  3. #3
    Petty Officer 2nd Class
    Join Date
    Jun 2013
    Posts
    134

    Default Re: Yamaha V4 115 HP 2 stroke - Cold starting problem!!!???

    Check/replace the diaphragm in the choke unit. You can also press the key in to activate the choke before starting. This will deliver more fuel to the carbs. There is also an emergency start on the choke. Try these things to troubleshoot. When you say you think you should replace the diaphragm of the fuel pump, do you mean in the choke unit or the actual fuel pump itself? As long as you prime the bulb on the fuel line until it gets hard, then a faulty fuel pump would not be the reason the motor isn't starting. You can easily troubleshoot fuel pump issues by priming the bulb while the motor is running, thus becoming your own fuel pump. Focus your energies on the diaphragm in the choke, or just replace the whole choke unit.

  4. #4

    Default Re: Yamaha V4 115 HP 2 stroke - Cold starting problem!!!???

    Guys I am having the same issues as you all and also posted a new topic. Did either of you figure it out? I don't suspect the fuel pump as fuel has gone thru it into the carbs. Fuel is not going from the carbs to the plugs. I'm wondering if it is the pulse lines not working.

  5. #5
    Petty Officer 2nd Class Natty Light's Avatar
    Join Date
    Jun 2012
    Location
    Memphis, TN
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    115

    Default Re: Yamaha V4 115 HP 2 stroke - Cold starting problem!!!???

    This is what two strokes do when it's cold.
    Mine does it.
    Crank it until it turns over. Sometimes it turns right off and makes kind of a humming sound. Crank it again. A couple of times and it will turn over, immediately hold the choke down and it will rev a little bit, this will keep it from turning off. Likely in cold water if you don't hold the choke down for a couple of seconds after it turns over it will die. Press the choke every time it acts like it is going to die. After about 15 seconds of this she is warm enough to stay running without your help. Much less of that needed in warmer water for me, but what y'all are describing is what I always see from my two stroke when the water gets cold. Same as you every start after that first one is a breeze with no choke needed, just a quick turn of the key.

  6. #6
    Ensign
    Join Date
    Dec 2006
    Location
    NC
    Posts
    900

    Default Re: Yamaha V4 115 HP 2 stroke - Cold starting problem!!!???

    I have also have a 115, 86 model, that is sometimes challenging to crank when cold or when it has not been cranked in a while. For mine I first make sure that I have a jump box handy just in case the battery is not fully charged. I then turn the ignition switch over with out the choke for 5 or 6 revolutions. When it does not crank I will them push the key in to choke it and a gain try to crank it for 5 or 6 revolutions. I will do this a couple of times turning off the key between attempts. If it still has not started I try it without choking again. It will usually fire somewhere in this sequence. As mentioned after that all it take is a bump of the key to get it running. If the motor acts like it is slowing at all use the jump box. Hope this helps someone.

  7. #7
    Petty Officer 1st Class
    Join Date
    Apr 2012
    Posts
    386

    Default Re: Yamaha V4 115 HP 2 stroke - Cold starting problem!!!???

    How cold is it in Copenhagen? I am in Florida, so cold to me is 70 degrees F. :-)

    You could choke the engine and play with it a little while putting the throttle advance forward, raising the engine speed. You play with it until it reaches temperature and then Bob is your uncle. Unless of course you have not got enough fuel coming from the carbs. What the choke plate does is create vacuum behind it pulling fuel from the carb orifices. If you have any blocked up, it won't draw enough fuel to start.

    Don't use starting fluid to start a two stroke!

  8. #8
    Vice Admiral
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    Sep 2008
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    MiddleTexas coast
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    5,163

    Default Re: Yamaha V4 115 HP 2 stroke - Cold starting problem!!!???

    And make sure you open the throttle/ fast idle some when choking for cold start as it needs air along with the fuel

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