Primer bulb never gets hard

[patrickj]

Got a 40 horse evinrude tracker that's having demons lately, got it all running good but the primer bulb will never get hard, brand new everything, tank, hoses, bulb filter, fuel pump, carbs rebuilt, all new hoses inside the motor, all new fittings, everything is hose clamped, just fills up about half way and once you idle for a few minutes it's empty. Mechanic couldn't figure it out I can't figure it out... any ideas... no gas comes out anywhere when you prime it

 

[ondarvr]

The bulb shouldn't stay hard, it will become soft shortly after the motor starts, but it should pump up and become hard when the motors not running.

Bulb empty's and the motor stops....Air leak, anti siphon valve stuck (if it has one), plugged pick up tube in the tank, fuel pump not mounted correctly, defective fuel pump, possibly bad squeeze bulb.

​Bulb never gets hard......air leak, float needle not seated, leaking fuel pump diaphragm, bad squeeze bulb.

 

[patrickj]

Motor runs great, like I said everything is new, replaced every part trying to get it to harden up. With the motor off the bulb only ever fills half way and stays that way when running

 

[ondarvr]

If it's running correctly it makes no difference what the bulb does, well, unless it collapses.

​But go back to my list if it's not getting hard and you want it to. And new parts don't mean good parts, squeeze bulbs are frequently bad when new.

 

[Vic.S]

Motor runs great, like I said everything is new, replaced every part trying to get it to harden up. With the motor off the bulb only ever fills half way and stays that way when running

When you prime the engine with the bulb tilt the bulb so that the outlet ( engine end) is pointing upwards. That way all the air in the bulb will be swept out. and when the the carbs are full it should feel firm, but not rock hard. If there is any air left in it it will feel spongy.

Once the engine is running it may feel less firm but if it becomes really spongy it suggests that air is being drawn in somewhere

 

[Silvertip]

Time and time again we cover this issue with "primer bulb won't stay firm". Physics 101 explains why it's impossible for it to stay firm when the engine is running. The simple answer is fuel is being "drawn" through it, not being "forced" through it. It gets firm when the engine is not running because the carb float bowls fill up and the inlet needle shuts off the fuel flow. If you really feel there is a problem, then the problem lies between the carb(s) and the bulb. If there were significant air leaks the engine would starve for fuel at higher speeds..

 

[patrickj]

When you prime the engine with the bulb tilt the bulb so that the outlet ( engine end) is pointing upwards. That way all the air in the bulb will be swept out. and when the the carbs are full it should feel firm, but not rock hard. If there is any air left in it it will feel spongy.

Once the engine is running it may feel less firm but if it becomes really spongy it suggests that air is being drawn in somewhere

That did the trick, gets hard as a rock that way, then softens as the motor runs

 

[patrickj]

Time and time again we cover this issue with "primer bulb won't stay firm". Physics 101 explains why it's impossible for it to stay firm when the engine is running. The simple answer is fuel is being "drawn" through it, not being "forced" through it. It gets firm when the engine is not running because the carb float bowls fill up and the inlet needle shuts off the fuel flow. If you really feel there is a problem, then the problem lies between the carb(s) and the bulb. If there were significant air leaks the engine would starve for fuel at higher speeds..

I never said it wouldn't stay hard, it would never get hard or even close to it, the bulb on this boat hangs down, it's a pontoon, so I guess it was trapping air in it, soon as I pointed it up it gets solid, thanks for all the help

 

[patrickj]

Maybe someone can answer 1 more question for me... boat off I have 12.4v running I have 13v at idle is that a good charge voltage?

 

[ondarvr]

12.4 indicates a low battery, 13 at idle might be OK, but it should climb to 14+ as the RPMs increase for it to charge correctly.

 

[jakedaawg]

Let it run for 1/2 Your before checking running volts. Preferably not on muffs.

Have battery load tested. Most parts stores do it for free.