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fuel bulb wont stay firm.

O

oil driver

Contributing Member
I changed tank,primer bulb,hose, and I unscrewed the fuel filter on my late 70's 115 Evinrude. With the filter disconnected ,fuel flows to it when pumping the bulb There is no visible fuel leak. Is the check valve in both tanks bad? Can somebody help?
 
Just exactly is the problem causing the question? The primer bulb is not expected to stay firm once you quit squeezing it.
 
I did not think 2 tanks could be bad but when I put the hose ( no end) into the tank, I got fuel to stay in the line and the engine started and stayed running. I am going to change the fuel pump. I am hoping that will help with the engine stalling at idle. Thanks for answering.
 
Aha! So do your tanks have the two little pins that get pushed in when you plug on the hose? The pin with the little brass washer around it has a teensy o-ring behind that washer. O-ring goes bad and it sucks air. Take it apart and replace all the o-rings. (Access by removing the round core plugs on the back side.)

All this is assuming the o-ring in the fuel connector is good. But you said it is new.
 

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I will do this. Thanks. After it worked with the hose I reconnected to the tank tube and saw the fuel ie. air bubbles go back into the tank. At least I have 2 primer bulbs now. If I can get this engine to idle down without stalling then I win.
 
I just gave the compression gauge back to Matt(bad news on my 225), so I guess I should break the piggy bank and buy one. Thanks for the info.
 
Member "fdgator" has given you the answer you need to cure your problem. My entry here is simply a bit of information pertaining to your "Fuel Primer Bulb".

Most fuel primer bulbs are simply laying around on the deck somewhere, under the gunnel, of bouncing around in the motor well. As such, they're laying horizontal. If the primer bulb pumps up hard, that indicates that the fuel system si loaded with fuel, including the fuel primer bulb and that its two (2) valves are in proper operating order.

Now, with the engine running and the primer bulb laying horizontal, the fuel level within the bulb drops to the halfway mark... this is the normal function of the primer bulb and is no cause for alarm. No, I don't know why this happens but it is just, as the saying goes... the nature of the beast.

If for some reason, one would desire the fuel primer bulb to stay full, it would be necessary to have the bulb secured in some manner in a upright vertical position with the outlet valve facing up.
 
What Joe just said, plus this: When you are mashing on the bulb and the carburetors are full, there is no place for any more gas to go, so you are creating pressure within it. But when the motor is running, the fuel pump is creating suction within the bulb as it lifts gas from the tank. In other words, the pressure is replaced by a slight suction.
 
To clarify this,in a normal situation the bulb gets firm after several pumps as the carbs are full. This never happened though I used a tank which worked fine on a different engine.(I put it on a different motor to check). I did get the 115 to start,but it stalls if I reduce the throttle in order to shift. It runs reasonably well at start throttle or higher. After I install a new fuel pump, I would guess rebuilding the carburetors. should be next. Or is there something else?
 
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