Bad primer bulb....maybe?

[kfa4303]

Hi all. Went to fire up the old beast ('66 20 hp) today in prep for a trip tomorrow and noticed that the motor was running poorly. It was revving up and down without any input from the throttle and was difficult to start, which is odd because it's usually a 1-2 pull motor. I realized that I had a fuel delivery problem due to an air leak somewhere in the fuel line. One of the fuel hose adapters seemed bad, so I went and got a new one. Now both fittings on either end of the fuel line leading from the tank to the motor are nice an snug. However, my fuel lines are not filling up as verified by the clear plastic fuel filter I have inline btwn the fuel pump and the carb. While it doesn't always stay full while running, it does usually fill when I prime the bulb prior to start. Now, no matter how much I squeeze the bulb it never fills. So I'm pretty sure that my primer bulb is bad, but I'm not sure how to test it to see if it truly is faulty. I tried disconnecting the fitting from the tank end and stuck the fuel line straight into the fuel to see if I could squeeze the bulb and get the lines to prime that way, but no dice. The bulb itself looks perfectly fine on the outside, but I'm thinking the valve(s) inside may be on the fritz. Somehow it just doesn't "feel" right (very subjective, I know). Anybody know how to test the bulb to see if it's good bad, or ugly? Thanks.

 

[Daviet]

Re: Bad primer bulb....maybe?

If you have a stickey valve in the primer bulb you can hold the bulb in the vertical position and squeeze it a few times and see if it feels like it pumping fuel properly.

 

[kfa4303]

Re: Bad primer bulb....maybe?

With the arrow on the bulb pointing up or down when testing? Thanks.

EDIT:

I tried squeezing it both arrow up and down and it didn't seem to work either way, so I guess that means the bulb is toast?

 

[Daviet]

Re: Bad primer bulb....maybe?

With the arrow up, but you tried that, maybe time for a new primer bulb.

 

[kfa4303]

Re: Bad primer bulb....maybe?

I think you're right Daviet. It's pretty old (+5 years), come to think of it. Even though it looks good on the outside, I think it's probably just worn out. How does a primer bulb work anywho? I guess it has a single, one way flap/valve in it that should've allowed me to draw fuel into the bulb without letting it fall back out again hence the vertical test.