Dunno?

Hi all
I'm currently working on a 72-73 merc 7.5 with this being said its not the one with the fuel pump built into the carb.

My issue is i can get it to pull over and run for about 5 min and then it seems the fuel line goes empty and the motor quits if if I prime the ball while its running sometimes it runs other times it still quits.
Not sure how much fuel that fuel pump should be pumping but it does not look like a whole lot.
also sometimes i go to prime the ball and its like the carb airlocks or something because no matter how hard the ball is squeezed it will not allow fuel in.


first off should the fuel pump be pumping a constantly noticeable stream.
second why does it almost seem to be air locked
third how may turns out should the low speed needle be.

I ask all this because I normally work on Johnson/Evenrude and have never encountered this issue.

thank you for your time
James

Re: Dunno?

The ball should get hard, if it didn't there would be a problem.

Look for an air leak in the fuel line, maybe at the connection fittings.

The fuel should pulsate when coming out, each rotation of the crank should product a spurt of gas.

About 1.5 turns, but it doesn't really matter, that's just a starting point, as long as you can get it running you just adjust it from there.

This trouble shooting would be exactly the same on a J/E brand.

Re: Dunno?

the ball does get hard but it dosnt pump fuel into anything
I have a clear line to check for fuel flow on my ball line and it like instantly goes hard and no fuel makes it to the carb.
Thank you
James

Re: Dunno?

Sounds like you may have a clog in the primer ball/ fuel line going into the fuel pump. If not, check the fuel line going into the carbs.
Scuba

Re: Dunno?

Squeeze bulbs go bad frequently, and even new they may not work well. So if it does it instantly look there first. Also check the connector fitting at the motor.