Bulb in fuel line not staying hard.

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rivertripp

rivertripp

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i have a 1980 75 hp Evinrude and the motor runs great, but when put into neutral or idle forward the motor will run for about ten to twenty min. the die out. When I got to prime the bulb in the fuel line, it has not pressure to it and I have to squeeze it about 5-10 times. Even after priming it though the bulb does not get pressurized. When my mechanic worked on it awhile back he used his fuel line and fuel tank, and everything worked great so we know the fuel pump and fuel pump lines work good and have no leaks. Any suggestions on what might be going on and what to do about it?
 
kenmyfam

kenmyfam

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Re: Bulb in fuel line not staying hard.

Are you using a portable tank ???
 
rivertripp

rivertripp

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Re: Bulb in fuel line not staying hard.

Already replaced the bulb and yes it is a 12 gallon portable gas tank from Bass Pro shops.
 
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boobie

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Re: Bulb in fuel line not staying hard.

You might want to get the bulb to where it holds pressure and then keep the pressure on it. At time start looking for any fuel leaks in the entire fuel system. Also look in the throats of the carbs to see if there is any flooding.
 
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emdsapmgr

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Re: Bulb in fuel line not staying hard.

The fuel line hose bulb is not supposed to stay hard. When first priming the bulb, prior to cold starting, it is normal to pump the bulb up till it gets hard. Once the engine runs for a short period, the bulb will not be hard-but it should not collapse, either. That's normal. If you have problems with the engine staying running, check to make sure you don't have an air leak in the fuel system, and that the floats are working properly in the carbs. If the engine runs fine when you constantly prime the fuel hose bulb, you may have a weak fuel pump.
 
rivertripp

rivertripp

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Re: Bulb in fuel line not staying hard.

The tank is vented properly made sure to check that first thing
 
jtexas

jtexas

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Re: Bulb in fuel line not staying hard.

emdsapmgr said:
The fuel line hose bulb is not supposed to stay hard. ...
Click to expand...

...while the motor's running. Just wanted to clarify. It won't be firm during operation cause the pump is pulling fuel through it -- but should be firm when the motor shuts off and stay hard all day. Seek immediate medical attention after 4 hours.

Listen close at the quick disconnect fittings (both ends) for the wheezing sound of sucking air while you pump the primer bulb. Or, those fittings will wear out over time, so if you haven't done so in the last few years, go ahead & replace 'em now. They aren't that expensive. If it doesn't solve the problem, keep the old ones as on-board spares.

In my experience, if the fuel pump diaphram gets perforated on that motor, gas will dribble out that hole on the back of the housing when you squeeze the bulb and also while the motor's running.

Try this: pressurize the line in the morning then check it after 5 or 7 hours. If it's still firm you know the fuel line is holding; suspect a weak fuel pump. If pressure doesn't hold for more than a couple hours (motor not running), it's a problem in the line. Any other result I think would be "inconclusive."

btw, the manual says that pump is not serviceable, but sierra repair kit #18-7820 fits it just fine.
 
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