mercury 40 hp

Discussion in 'Outboard Maintenance' started by steve77777, Jan 4, 2014.

  1. steve77777

    steve77777 I Love microskiff.com!

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    the boat runs great but sometimes idling and going slow the ball gets soft and engine dies, and also if i turn it off for 30 minutes the ball is soft.I ran it for 30 minutes with no problem then i docked it ,waited 30 minutes started back up then tried to go and stalled out ,bulb was soft then i squeezed the bulb a bunch and it started right up and took off and ran great again,the mechanic said bulb looks kinda new-could this be a bad ball? has this happened to anyone of you,please help thankyou....
     
  2. Dillusion

    Dillusion devilray snob

    Sounds normal...every primer ball I have ever owned has needed to be primed again after 30 minutes. Not out of the ordinary.
     

  3. Creek Runner

    Creek Runner Well-Known Member

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    Going to have to disagree with you on this one Matty, no engine should stall from idling or going slow. Either its loading up or starving for fuel.

    Also there really shouldn't be a need to pump the primer bulb after setting for 30min. 4 Hours yes but not 30min.
     
  4. mark_gardner

    mark_gardner I Love microskiff.com!


    I agree with creek  ;) my guess is that its starving, possibly a leak....how old are your hoses and primer bulb ?
     
  5. steve77777

    steve77777 I Love microskiff.com!

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    well i bought the boat used like 3 months ago and have had this issue,the primer bulb looks new and hoses look good,question would the leak have to be from the primer bulb to the engine? or from the bulb to the tank? and is there a way to find this leak? should i replace the ball first then if its not that go to the next thing since the ball is i guess under 30.00..? its kinda weird when it does it just random but when its doing it i just squeeze the ball and its good again for awhile.
     
  6. steve77777

    steve77777 I Love microskiff.com!

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    also could it be the tank is in the front of the boat?does this play into anything?
     
  7. HaMm3r

    HaMm3r Well-Known Member

    I too must disagree about the primer bulb losing prime. I pump it a couple times at the start of a trip and never touch it again the entire day. There may be half a day fishing in between motor runs and it still stays primed. Even after trailering a couple hours home sometimes, it just fires right up for driveway flushing.

    I run a Merc 25hp, 2-stroke and use one of the new EPA-mandated tanks with the old-style, non-EPA approved cap. Just for comparison purposes. ;)
     
  8. Dillusion

    Dillusion devilray snob

    Oh, I must have forgot about that part of his post while addressing the need to reprime after thirty mins issue.

    Yes losing prime at idle isn't normal...my engine idled for 20 minutes today at the ramp without dying out in neutral.
     
  9. steve77777

    steve77777 I Love microskiff.com!

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    im gonna put a new bulb on and ill let you know in a few weeks if it fixes the problem ,thankyou everybody
     
  10. steve77777

    steve77777 I Love microskiff.com!

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    so i put a new primer bulb on and ran it through no wake zones today for 2 hours and every ten minutes it would putter and stall ,then finally when i heard it start to stall i would pump the ball and it would run another ten minutes,now process of elimination ,could it be the anti syphon valve or could the water seperator have anything to do with this? any help would be appreciated thx....
     
  11. DuckNut

    DuckNut Brandon, FL

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    All other items are just a guess but start eliminating the obvious and cheap.

    The primer bulb is an easy way to siphon. If the siphon is working and then stops it is because it has air.

    My first and simple guess would be to replace all of the fuel line, clamps, fittings and filter under the cowling. Air up high means siphon stops working.

    Also, make sure you are not creating a suction on the tank.
     
  12. steve77777

    steve77777 I Love microskiff.com!

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    ok all fixed,i hooked new gas tank up, then the same thing happened then i took it and had the fuel pump diaphragm replaced and all is running perfect,it wasnt pumping while in lower rpms but at higher speeds it was pushing harder so the seals where working but only at higher speeds
     
  13. 'Nano-Skiff'

    'Nano-Skiff' It's not the size of the boat....

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    I love it when there is an answer on these types of threads. Have fun.