#2 carb starving for gas

[fishin0001]

Mercury 40hp 4cylinder 2 stroke oil injection seems #2 carb is starved for gas when at idle put my palm over top carb motor wants to die normal,put my palm over bottom carb motor wants to take off...same with trying a little sea-foam...cleaned both carbs re-adjusted floats to spec and same results,I noticed the top carb was about 1 1/4 turns out and bottom was 2 1/4 tried to get them the same with same results any ideas....thanks for any suggestions

 

[jimmbo]

Either a low fuel level, plugged idle/low speed circuits, carb to block gasket leaking, maybe internal blockage in the fuel line to that carb. How does it run at speeds faster than idle? Careful though, a lean cylinder can become a pooched cylinder in the blink of an eye

 

[fishin0001]

runs strong but better while closing air intake,what are the signs of a pooched cylinder..I did notice #1 plug looks black and 2,3 and 4 are cleaner...I also pulled each plug wire while running and motor would miss...will check all that you said

 

[jimmbo]

Pooched meant scored. Symptoms include rough running and low power, and often a sooty plug. Have you done a compression test?
The top two cylinders are fed by the top carb and the lower two are fed by the bottom carb. If the compression checks out, you might have multiple problems, like #1 might be misfiring(ignition problem) and the lower carb is lean
Start first with a compression test and a spark test

 

[fishin0001]

Thanks will do

 

[fishin0001]

got the compression test done and I got 119 to 120psi on all 4 cylinders after I warmed her up....herd somewhere you have to have the throttle wide open but my throttle wide open prevents you from starting engine

 

[racerone]

Throttle position just does not matter on a 2 stroke.----An old tale that just does not go away !

 

[fishin0001]

seems the owner before me tried to play around with the air fuel mixture ..thanks