Please help Figure this one out,your a hero

jbeener1 · May 18, 2013

Ok my boat mechanic and myself are stumped. I have 1986 Evinrude 9.9 electric start,it runs fine except at wide open throttle then it will run about 50 yards and act like its running out of fuel,the minute you squeeze the the gas line bulb it takes off and runs about 50 yards again. What we have done is changed fuel pump twice with aftermarkets,changed fuel lines from tank to motor,changed fuel lines inside motor,cleaned and put in carb kits twice,new plugs,compression is good,firing is good. We can see fuel running from fuel pump to carb in the clear fuel line,put new gasket and the thing down in the fuel tank,changed out stator with a used one. I can see air bubble in the fuel line that runs from fuel pump to carb,dont know if bubbles are to be in the line. Please help. Thank you

Lightning1 · May 18, 2013

Re: Please help Figure this one out,your a hero

Check to make sure you are getting a pulse to operate the fuel pump.

jbeener1 · May 18, 2013

Re: Please help Figure this one out,your a hero

Lightning1 said:
Check to make sure you are getting a pulse to operate the fuel pump.

I put my finger over the pulse hole,i could feel a little sucksion and a pulse to blow outward

oldcatamount · May 19, 2013

Re: Please help Figure this one out,your a hero

There shouldn't be any air in the fuel system at all, but, how to pinpoint the air leak will be tough. Something somewhere is either loose or cracked. If it were me, I would start at the carb and work backwards to the tank. Double check everything (again), change all clamps.

Will Bark · May 19, 2013

Re: Please help Figure this one out,your a hero

Agree on the air in the line; the harder it runs the more air is sucked into the pump and carb til there's not enough gas to keep running. Got to find that leak. Good luck

durban · May 19, 2013

Re: Please help Figure this one out,your a hero

try changing the diaphragm in the fuel pump

Chinewalker · May 19, 2013

Re: Please help Figure this one out,your a hero

Vent open on tank?

doityourselfer1 · May 19, 2013

Re: Please help Figure this one out,your a hero

Check all your connections!! The same happen to me on my 1996 johnson 112.make sure all your clamps are tight.i had the walmart brand kwick connector on my gas tank.it was sucking air since day one. Change that to a simple brass connector. Use silicone tape on the threads.There is a connector at theend of the fuel line that connects to the engine.i changed mine twice and was still sucking air. Change that to a original OMC!! It looks the same, but it is not tight fit.runing your engine with airbubbles can cause the engine runing lean.runing lean is not enough lubrication!!mix your fuel 32 to1 for the next tank. Make sure use johnson/evinrude oil only!!! Good luck to you.

Watermann · May 19, 2013

Re: Please help Figure this one out,your a hero

doityourselfer1 said:
Check all your connections!! The same happen to me on my 1996 johnson 112.make sure all your clamps are tight.i had the walmart brand kwick connector on my gas tank.it was sucking air since day one. Change that to a simple brass connector. Use silicone tape on the threads.There is a connector at theend of the fuel line that connects to the engine.i changed mine twice and was still sucking air. Change that to a original OMC!! It looks the same, but it is not tight fit.runing your engine with airbubbles can cause the engine runing lean.runing lean is not enough lubrication!!mix your fuel 32 to1 for the next tank. Make sure use johnson/evinrude oil only!!! Good luck to you.

I second the no junk fuel lines. I too had trouble using the stiff after a season Attwood crapola line. I shelled out for the real deal OMC fuel line / bulb / connectors and after 6 years it's still soft and pliable with ZERO leaking or trouble.

Some where upstream of your line you can see air bubbles in, there is a leak, if it allows air in then gas will leak out unless it's in the pick up in the tank that is.

Rick. · May 19, 2013

Re: Please help Figure this one out,your a hero

I've hooked clear tubes from pump to carb. before and always see air in the line. I think some air is ok and normal. It's when there is insufficient fuel that you will see a problem. A full carb. on a 9.9 should go more than 50 yards even with the fuel disconnected ( my guess as I've never tried that). The was a post recently and it turned out the fellow had the wrong jet in his carb. I'm at a loss right now with yours but just wanted you to know some air in the line is IMO normal. It is trapped there but the fuel still goes by it. Best of luck. Rick.

Tim Frank · May 19, 2013

Re: Please help Figure this one out,your a hero

Is this motor new to you....and if it is not, is this a new problem, or has it done this since you got it?

Also, it is one thing for an amateur to change a fuel pump "on spec" instead of actually testing it....(it's not a difficult test)...., it is quite another for a so-called "pro" to throw 2 pumps at an engine for no good reason.
(you use a gauge to measure pump output...if it is OK, it's OK. if it is not, it might be a compression-related problem rather than a FP issue.) etc.

I'd be looking for another mechanic.

My first test would be to bypass the two "quick connect" fittings on your tank and the engine. The o-rings in the fuel line fitting are prone to wear....and I've had the metal barb on the engine fitting wear over time as well. Also, as someone said already....beware non-OMC gas line fittings. There are many knock-off brands....and some of them simply don't work....and some of the brands are almost identical in appearance across their line....so what looks like the correct unit to match MC is actiually intended for a different outboard brand.

F_R · May 19, 2013

Re: Please help Figure this one out,your a hero

Clear fuel line should be outlawed. Why? Because you can see the air bubbles in it, which are normal.

Stop guessing, test it. Temporarily tee a fuel pressure gage in the line between the pump and carburetor.

jbeener1 · May 19, 2013

Re: Please help Figure this one out,your a hero

Fuel pump is new

jbeener1 · May 19, 2013

Re: Please help Figure this one out,your a hero

Yes tank vent is open

jbeener1 · May 19, 2013

Re: Please help Figure this one out,your a hero

We did a compresion check threw the spark plug holes and they were fine,my fuel line is connected with a brass fitting on the tank and runs threw to the fuel pump,no quick disconnects. Ive had the motor for aound 6 yrs. this problem started september of last yr. Havent used a gauge to test fuel pump but have tryed to new pumps and tried a different tank and fuel hose. Thanks for your help.

Faztbullet · May 19, 2013

Re: Please help Figure this one out,your a hero

I had a rental toon with a 28 special that did this and what it ended up being was float hinge was worn and would stick in the closed postion. Whenyou pump bulb it popped it loose and refilled carb and it would take off again...

jbeener1 · May 19, 2013

Re: Please help Figure this one out,your a hero

The motor calls for a 100/1 ratio. Is that was i should use or go down to a 50/1?? I also use a sta-bil ethonal treatment.

jbeener1 · May 19, 2013

Re: Please help Figure this one out,your a hero

The fuel lines are Baracuda brand.

jbeener1 · May 19, 2013

Re: Please help Figure this one out,your a hero

We have checked and checked for fuel coming out of any connections and cant find any. Anyone know about aftermarket fuel pumps? are they ok? i know theres good and bad in all.

nwcove · May 19, 2013

Re: Please help Figure this one out,your a hero

not hard to bypass the fuel pump to rule it out completely. ive seen one motor that acted "somewhat" like yours tho, was just a matter of cleaning the ground wires from the powerpack. ( a classic case of ignition issues mimicking fuel delivery issues)

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