no fuel to carb while in neutral

[airraider]

... well the title pretty much says it ... i can start the motor if i throttle up in neutral but as soon as i drop back into neutral , i am not getting any fuel .. where would you guys look?

 

[Sunfish12]

Re: no fuel to carb while in neutral

You need to check for an air leak from the tank pickup to fuel pump. Squeezing the ball will tell if there's a leak between the ball and the fuel pump. Could have a pin hole in the pump diaphragm, if the pump hasn't been rebuilt in a long time it would be good to do.
What year and model?

 

[MaxTorque]

Re: no fuel to carb while in neutral

Given the limited information, I would suspect the Idle Air Control (IAC) valve. I have a Mercruiser Mag 350 MPI, symptom were that the engine would stall when put into idle, and I could only start the engine if I opened the throttle slightly before starting the ignition. Once started the engine ran normally until placed into idle.

Here's some reference: http://www.ehow.com/list_6046295_signs-idle-air-control-sensor.html

 

[Mi duckdown]

Re: no fuel to carb while in neutral

Your title tells nothing??? More info.

 

[Silvertip]

Re: no fuel to carb while in neutral

Agreed -- the only thing we have to work on is that this is a Mercury engine (and only since the question is posted in the Merc forum). We have no idea what year or HP. How do you know it is not getting any fuel. Just because the engine dies in neutral doesn't mean it is not getting fuel. For all you know the idle speed is set too low.

 

[airraider]

Re: no fuel to carb while in neutral

sorry about the lack of info, very tired when i posted... Its is a 83 mercury 50 4 cylinder 2 stoke ser. 6277090 ... not sure when or if the pump has ever been rebuilt .. bulb does get firm ... only making a guess as its not getting fuel , from judging how it dies like it is getting no fuel .. no spudders or coughs .. if there is anyway to test this , i would appreciate the advice , or if there is more information i need for you guys to help me please point me in the right direction.. thanks

 

[CharlieB]

Re: no fuel to carb while in neutral

FIRST, disconnect the fuel line between the fuel pump and carbs, crank the motor but do not start it, observe the fuel flow, it should be a strong pulsed flow.

SECOND, install a temporary clear hose between the fuel pump and carbs, start the motor and observe for any air bubles passing thru the clear hose indicating air sucking into the system somewhere before the pump.

It is always a good idea to verify a hot 7/16 inch spark on all cyls as well as doing a compression test to verify the basic mechanical condition of the motor. Both are easily done in a short time and eliminate a LOT of guessing what could be wrong.

Once all the above are completed and pass, then it is time to clean and adjust the carbs.