Yamaha 2012 four stroke 115hp fuel prime while sitting for a couple weeks and won’t start…

YamaDog115

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Joined
Nov 12, 2022
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My Yamaha 2012 115 hp four stroke after sitting for a couple weeks loses its prime and the primer bulb gets soft. I pump the bulb but sometimes it does not get truly hard in the motor will not start and I have to keep pumping the bulb. I replace the primer bulb and I replace the fuel line from the water separator and bulb to the tank with the same symptoms. I notice under the cowl that the small fuel water separator has air in it is that normal? Once I do get it primed and the bulb is hard the motor runs fine and will run all day with no problems. Where else could I have a leak is it in the fuel water separator under the cowl or is it possibly in the fuel tank. I have intermittently over the past smelled gas in the consul where the access panel to my fuel tank is Located be a telltale sign I have a leak in the fuel pick up in the tank? Or is this a fuel pump problem because I said before there’s air in the fuel water separator under the cowl or is that supposed to be like that?
 
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dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
16,342
My Yamaha 2012 115 hp four stroke after sitting for a couple weeks loses its prime and the primer bulb gets soft. I pump the bulb but sometimes it does not get truly hard in the motor will not start and I have to keep pumping the bulb. I replace the primer bulb and I replace the fuel line from the water separator and bulb to the tank with the same symptoms.
The primer bulb is not designed to hold pressure long term. It’s there simply as a means to get fuel to the fuel pump on “cold” start.

The primer bulb is a simple hand pump with a simple (plastic) back flow preventer when held in the upright vertical position.

Off vertical, the primer bulb fuel is “open” back to the fuel tank.
I notice under the cowl that the small fuel water separator has air in it is that normal? Once I do get it primed and the bulb is hard the motor runs fine and will run all day with no problems. Where else could I have a leak is it in the fuel water separator under the cowl or is it possibly in the fuel tank.
Any “worm screw” hose clamps in the fuel delivery system? They’re notorious for leaking
I have intermittently over the past smelled gas in the consul where the access panel to my fuel tank is Located be a telltale sign I have a leak in the fuel pick up in the tank? Or is this a fuel pump problem because I said before there’s air in the fuel water separator under the cowl or is that supposed to be like that?
Sending unit gaskets can leak but most “unknown” smells are from old, permeating fuel hoses. The fill hose is often the over looked culprit
 
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