175 stalls in idle

[johnnyraff]

Engine runs great when powered up but stalls out at idle. Not sure if its the fuel line, I did find a crack in one of the smaller lines that went into engine. I did fix that and Im hoping it was the problem. Also no fuel in the ball I pump it up and seems to be ok for a while. Hoping that cracked hose was the issue. New to boating so any help would be great.

[Solarman]

It might help for those of us on this side of the screen to know a little more about your motor?
For example: is it 2 (DT) or 4 stroke (DF), the age (year model) of the motor could help. Maybe even the hours of the motor. Apparently it is a used motor, if new to boating, not idling, but starts up ok? Is this a carb motor, or EFI (electronic fuel injection) what about any compression readings? There were problems when bought, so hopefully you got a fair deal?

Post back to help us, help you. Good luck.

[johnnyraff]

It’s a 2007 4 stroke , got a pic of cracked hose hopefully it was the issue . Trying to post a picture but won’t upload

[artdf175]

Where was the cracked hose, before the fuel bulb or after (the engine side)?

[johnnyraff]

This was the cracked hose not fuel line but it definitely goes into the engine Screen Shot 2019-07-10 at 1.51.53 PM.png

[johnnyraff]

Hard to see in the picture but it runs into engine compartment down into the well, maybe air line?

[tsturm]

water pressure / spedo tube in your pict

[johnnyraff]

water pressure / spedo tube in your pict

guessing this would not cause the issue Im having ?

[artdf175]

did you check the IAC valve?
this valve is designed to regulate the RPM

[johnnyraff]

No I didn’t would that suck fuel from the ball if it wasn’t working? There was no fuel in the ball

[Moonlighter]

Seen similar symptoms several times - one definite possibility is that the anti-syphon valve on your fuel tank is failing and cutting off fuel to the engine at low revs. At high revs the engine is sucking more fuel through and can keep the valve open, but a low revs the fuel volume is too small to keep it open. So it shuts off and starves the engine, and the bulb goes flat.

The solution is easy - undo the fuel line where it attaches to the barb at the tank, then unscrew the antisyphon valve which is part of that fitting. It has a ball spring and seat inside it. Take it to the work bench and punch those parts out so that you now have a straight through barb. Reinstall it on tank and reconnect fuel line.

[marcus270]

what is the reasoning for the anti-siphon valve?is that there to prevent fuel spillage in case of a capsize or sinking?

[Moonlighter]

It is to stop fuel flowing backwards to the tank.

It is completely unnecessary on outboard powered boats, so no harm done by getting rid of it. In fact there is a good argument that getting rid of it is a sensible preventative action.