115 johnson runs fantastic--until!!!

hi folks hope you can help me as i am nearly bald headed over this problem. the engine is a 2003 60 degree looper,model #j115pxsts. first start of the day squeeze the bulb,turn the key,push the key in and it starts immediately idles thru a half mile of no-wake zone better than great! jumps up on plane smooth strong power 40 mph for five or six miles just a singing it would make you proud never a hiccup,burp,spit or miss. now here is the problem. if i shut it down to fish for 2-3 hours, i repeat my initial starting procedure and let it idle for a few minutes and put it in gear advance throttle lever it will stutter and die. take it out of gear and bump the key it fires right back up put it in gear and advance the throttle it stutters and dies, this scenario continues thru 5 or six attemps with me feathering the throttle until it finally catches and i am able to take off. it is maddening i have a recent carb job,new fuel/water separator,new wires ,new plugs,new squeeze bulb, carbs were linked and synced,fresh fuel and two johnson certified mechanic that are mystified i promise a case of your favorite beverage to the wizard. thanks for your help Snukes.

Re: 115 johnson runs fantastic--until!!!

After the 2-3 hour layover, do you actually pump the fuel primer bulb up hard again? If not do so.

My line of thought is that perhaps the anti siphon valve at the tank is sticking open (or is non existent). This may allow the majority of fuel (not all) which would obviously be needed for high rpms to drain/siphon back to the tank.

Re: 115 johnson runs fantastic--until!!!

Joe Reeves said:

After the 2-3 hour layover, do you actually pump the fuel primer bulb up hard again? If not do so.

My line of thought is that perhaps the anti siphon valve at the tank is sticking open (or is non existent). This may allow the majority of fuel (not all) which would obviously be needed for high rpms to drain/siphon back to the tank.

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I'm with this one as well. First thoughts I had before I scrolled down to Joe's reply !!!

Re: 115 johnson runs fantastic--until!!!

Joe Reeves said:

After the 2-3 hour layover, do you actually pump the fuel primer bulb up hard again? If not do so.

My line of thought is that perhaps the anti siphon valve at the tank is sticking open (or is non existent). This may allow the majority of fuel (not all) which would obviously be needed for high rpms to drain/siphon back to the tank.

Click to expand...

thank you for your response, in fact i do squeeze the bulb up after the lay over. the boat is a dusky 17, comes from the factory without an anti-siphon valve. dusky says they no longer put them in because of problems with them that ruined too many engines. any other thoughts come to mind? thanks. let me bounce my theory off of you, see if it makes sense. when i turn it off after a run the water drains out of the cooling system but the engine is still hot. could this cause gas to evaporate leaving a sort of vapor lock ? mind you that after 2-3 hours the engine is not hot and this has happened to me at nite in 50 degree weather. oh i forgot to mention that at any time within the first hour of down time i can just bump the key and it fires right up and away i go... what the heck is a vapor pump-separtor and what does it do ? am i on the right track here ? thanks for your expertise, snukes

Re: 115 johnson runs fantastic--until!!!

you also might be flooding it. do you tilt the motor when it is off and you are fishing?

Re: 115 johnson runs fantastic--until!!!

Inspect the stator under the flywheel for cracks, and most importantly for leakage. If there should be any substance oozing from that stator, dripping down upon the powerhead area, replace it. This oozing would indicate that the stator is "melting down" which would result in a voltage drop from the stator to the powerpack, which in turn would result in weak, erratic, or no ignition when it reaches a certain temperature.

Stators that start this "melt down" process may work perfectly when cool, or even at a medium temperature, but as the temperature increases, it fails. May not be your problem but it's something that should be looked at.

Re: 115 johnson runs fantastic--until!!!

tashasdaddy said:

you also might be flooding it. do you tilt the motor when it is off and you are fishing?

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thanks for the reply, no i do not tilt it while i am fishing but i have never smelled fuel or seen the residue in the water around the engine as you would expect if it was flooded.. it rather acts if it is starving for fuel.. if it was spark wouldn't it show up at idle or wot ? it purrs like a big cat either speed.. snukes

Re: 115 johnson runs fantastic--until!!!

Be careful as you will need a flywheel lifting tool to remove flywheel to check stator. You cannot see it to check for melted windings unless flywheel is removed.