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Mercury 9.9 4 stroke wont run with out choke pulled.

T

Tpot

New member
I have pulled the carb and cleaned it thoroughly and reinstalled it and the motor would start up just fine but I would run it for about 5 minutes shut it off for about 5 minutes and then it will not run again with out the choke pulled. Any suggestions on what it could be?
 
Is engine running at normal temp, telltale stream should be warm when she is warmed up, Do you have to leave the choke on fulltime for it to run,or use choke just to restart and then push it in once she fires? What does the plug look like when this issue arises? wet? Dry? Is primer bulb going flat? Possible air leak in fuel lines?
 
johnnygjr said:
Is engine running at normal temp, telltale stream should be warm when she is warmed up, Do you have to leave the choke on fulltime for it to run,or use choke just to restart and then push it in once she fires? What does the plug look like when this issue arises? wet? Dry? Is primer bulb going flat? Possible air leak in fuel lines?
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The only time I can turn off the choke is when I have over half throttle. Other than that I have to have the choke on or it immediately dies. I plan on checking the plug tonight once I get off work. Not sure about what the primer bulb feels like when it is running. It seems to me that there is not enough fuel flowing through the carb. I have cleaned the carb twice now and each time right after the install it would run fine for a little bit then once I shut it off and try to restart it the same thing happens.
 
Have you tried pumping primer bulb while she's running to supplement fuel pump, Have you physically gone over every fuel line and clamp from tank to carb, How old is fuel? Old fuel in tank from last year? Is your tank vented properly? Inside of tank inspected? Pickup tube in tank getting clogged? Sometimes there's a small screen at the bottom of that tube. Check operation of primer bulb again,does it pump up firmly,before starting engine
 
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I have already checked the fuel pump by taking the fuel line off the pump to make sure it is pumping enough fuel
 
How were the floats adjusted,finger pressure is more than enough to do damage on the needle and seat, You need to answer our questions so we can help you
 
Its new fuel and the primer bulb does get firm when I squeeze it while the motor is off. The tank is older I was thinking of replacing the whole tank and hose. All the other fuel lines are in good shape and I have replaced the fuel filter. I am 99% sure it is a carb issue because after I clean and reinstall it the motor will run fine. What I am thinking is that there was still some old fuel in the fuel line coming from the fuel tank to the motor that keeps clogging the carb. Is there any certain settings for the jets or do they all just get lightly seated? As for the float it is in good condition no pin holes or anything and I have not tried to adjust the float at all.
 
I removed the carb once again and the pilot jet was clogged again. Any suggestions on how to keep this from happening?
 
It's sounds to me like you've got some trash somewhere in the fuel system and you have to find it and remove it. If Old metal tanks have any rust visible on the inside it will continue to break loose and cause this, also check inside the fuel pump if it is serviceable, had one a while back doing the same thing fuel pump was full of sediment.
Good luck
 
I would imagine a non restrictive inline filter could be in stalled, Easier than pulling the carb. jet!! You need to inspect the inside of your fuel tank :cool:try a friends known good tank and run your motor on that one as a test
 
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Just watched a video of a fellow with same problem; inside of gas line was breaking down and sediment was causing jamups in carbs. He recommended changing gas line. ALso mentioned to check the interior filter on the fuel system; on his engine, it was located underneath the coil on side of engine; I never knew my engine had one.
 
I had same problem with 2006 4 stroke 9.9 and after pulling spark plugs determined it was running lean.
So with engine running I changed the setting on the fuel/air adjustment by turning it clockwise(rich) about 1/4 turn and after
waiting about a minute for engine to adjust, pushed in choke and engine finally stayed on.
 
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