1 Leaking Carb, 3 others don't fire

[Hardcore]

1994 140hp Evinrude Looper, had an issue with it only running off the port 2 cylinders. and also it wouldnt prime with the bulb (wouldnt suck from the tank)

pulled the cover off the carbs and lots of gas poured out. when i pumped the bulb, gas came pouring out of the bottom port carb from the small hole bottom center. i assume this is a faulty float seal (inlet valve) but would this cause the other cylinders not to fire? i checked the other 3 bowls and they had gas in there.

i am planning to rebuild the carbs but i am confused because the original symptom was that when i would pump the bulb gas was not drawn from the tank as if there was a blockage in the motor.

my theory is that the gas is drawn to the leaking carb causing the others to be starved? does this sound right? there are 4 fuel lines, 1 for each carb that branch out from one main hose.

 

[noelm]

Re: 1 Leaking Carb, 3 others don't fire

not pumping fiuel from the tank via the fuel bulb has almost nothing to do with the carbs, you can disconnect the fuel line from the carbs and pump fuel all day with the bulb, I think you are chasing a fault, but got thrown off and have now gone onto something else that has nothing to do with the original fault, first step, check the spark on all cylinders, is it a nice strong blue spark on all 4? are the plugs OK, do they all look the same? replace them anyway, while they are out, do a compression test.

 

[Hardcore]

Re: 1 Leaking Carb, 3 others don't fire

there is some correlation its just hard to explain.

the motor ran flawlessly and now has this all of a sudden. compression is very good and almost perfectly even.

it runs but only on the cylinder that has a leaking carb and barely on the cylinder above it and not at all on the starboard 2. spark is good on all 4.

when i pump the bulb, gas spews from the one carb which, strangely is the only cylinder that really runs.

 

[Silvertip]

Re: 1 Leaking Carb, 3 others don't fire

Well sir -- start the corrective action by fixing the overflowing carb. Obviously the needle and seat are not functioning properly. If the engine is running, spray a fuel/oil mix into the carbs that are not functioning. If the other carbs had fuel in them, then that's not the issue. Have you checked for spark on the two cylinders that are dead? Engines need fuel, air, spark, and it all needs to happen at the right time. Miss any one of these and you have a dead cylinder.