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gas shooting out top of carb 4 hp 4 stroke

infinityron

Contributing Member
I have a 2003 mercury 4hp 4 stroke. been a little stubborn starting lately. I changed the in line fuel filter under the integrated tank. I confirmed fuel flow after the pump. Got it started and it seems to want to run and idle ok, but there is raw fuel spitting heavily out of two little nipples at top of carb continuously. Obviously i shut it down. I suspect a float problem, but wondering it its easier just to unbolt the whole assembly and replace with another carb assembly and not cost prohibitive. What is causing the gas to spit and .......why are those two nipples/barbs/fittings on there and why arent they plugged?
 
I have a 8HP four stroke and I replaced the card for under 100.00 with one from Amazon. Ran fine for a year but began hard starts again and other issues. Bought another carb and using motor once a week. These little carbs have so many ports that no matter how many times i've tried, i just can't get them to run right. Hundred bucks a year may seem like a lot but it is worth it too me. Hope that helps.
 
I have a 8HP four stroke and I replaced the card for under 100.00 with one from Amazon. Ran fine for a year but began hard starts again and other issues. Bought another carb and using motor once a week. These little carbs have so many ports that no matter how many times i've tried, i just can't get them to run right. Hundred bucks a year may seem like a lot but it is worth it too me. Hope that helps.

You're right. replace whole thing is cheap enough. I did, however go ahead and remove mine and checked out the float needle It was stuck open so I carb cleaned it and exercised it and put it back together. Fixed the problem and its running good again.
 
I suspect the float needle is either gummed up or stuck. pull the float and needle to inspect. the needle should move from its seat when the carb is held upside down once the bowl cover is removed. hope this helps.
 
I suspect the float needle is either gummed up or stuck. pull the float and needle to inspect. the needle should move from its seat when the carb is held upside down once the bowl cover is removed. hope this helps.
yeah, as mentioned above, the float needle was stuck. fixed it
 
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