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Loss of fuel prime

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bstig75

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I have a 95 90 horse Mariner with a new powerhead with approximately 125 hours on it. Lately, it has been losing prime and the engine will die. I have to pump the bulb many times before the engine will start again. Yesterday I noticed that when I added throttle to come on plane the engine seemed to be missing at lower throttle position, once the rpm's were up it ran fine. When trying to run it up on the trailer yesterday, the engine would die but would restart, then when throttle added would die again. Your thoughts.
 
Bulb should be pumped up to "hard" prior to starting. If it won't carb needle valve leaking or bulb check valve (the one back to the tank) leaking. While engine is running bulb soft, maybe depresses half way with minimum pressure...shows fuel pump is getting fuel pulled up to the engine.

Fuel pump diaphragm may be old and stiff. Valves in fuel pump leaking.

Air in the lines due to cracks in the internal hoses...10 years was my age number for starting to have fuel line problems.

Others addressed these issues. These are my points of interest if I had that problem.
 
"This problem is intermittent." Cracked internal engine fuel line(s) would be my guess. On the fuel pump, the diaphragm gets stiff with age. Kits are cheap and work is easy. Would recommend you change it at your convenience.
 
bstig75 said:
Don't know how old the fuel pump is. will check lines and filter for possible leaks. This problem is intermittent.
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Would this problem also cause the engine to die and not restart while running?
The bulb on my 115 Mariner never gets hard while pumping, and the motor has left me on the lake several times lately.
 
BULB must go hard.------If it does not there is a leak.------On hoses.-----Or carburetor float valves.-----Or fuel pump diaphragm is ruptured.
 
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