Fuel filter not staying full 98 merc 150/105 jet

case7409

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Jul 12, 2012
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Hello everyone. So i have a 2072 Seaark Jon boat with a bow mounted fuel tank. And a 1998 mercury 150/105 carbed 2 stroke. And ever since i got this boat I've been having this problem at least i think it may be a problem. I have a inline clear fuel filter about a foot in front of the primer bulb. And overtime i run the filter almost completely emptys out. And some time it gets air locked and makes it hard to start. Any ways i rebuilt the fuel pump, ran all new fuel lines, new bulb, new anti siphon valve. And still the same issue. Any ideas or is this normal. Thanks nathan
 
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Joined
Aug 8, 2013
Messages
57
Re: Fuel filter not staying full 98 merc 150/105 jet

So how does the motor run when on plane? Does it surge looking for gas, or does it die out everytime after 2-3 minutes on plane?

The empty fuel filter sounds odd, but they only run 1/2 - 3/4 full while on plane.

This wouldn't cause a restart issue unless the motor died right before that. Your motor isn't starting off the fuel in the primer line, it starts and runs off the gas in the float bowls.

Next thing I'd do is substitute the anti siphon valve with just a barbed fitting (no check valve). If that helps, then the lift pump is past it's maximum for vacuum. This can be due to air leaks at the cowling fitting, or maybe a gas tank vent that is blocked.
 

MH Hawker

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Jul 13, 2011
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5,516
Re: Fuel filter not staying full 98 merc 150/105 jet

Mine dose the same thing, but has never caused a running problem, the air in the line will reach the high point and that's normaly a filter.
 

Mi duckdown

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Apr 14, 2007
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2,575
Re: Fuel filter not staying full 98 merc 150/105 jet

Is there not a filter under the hood, on the motor? Don't need 2 filters.???
 

case7409

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Jul 12, 2012
Messages
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Re: Fuel filter not staying full 98 merc 150/105 jet

Its never ran out of fuel or surged. And i don't have a tach cause its a tiller handle. And the filter runs less than 1/2 full. That's what bugs me i don't want the motor sucking air and leaning out.
 
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