1990 SP Fuel system

[Twigg1012]

Forgive me as I am not well versed with carbs, let alone priming them.

Just bought a 1990 SP with a primer that does not prime? Replaced the primer and same issue. It seems the primer is routed from a tee on the supply line(clear line), then to a port on the carb (red line). I do see fuel move in the supply line to the water separator but more so back and forth, it doesn't actually end up anywhere. Cranking the engine it doesn't seem to be able to pull fuel through the line due to the air but will run with a squirt bottle. Does this look like the correct setup? I will be replacing the fuel selector when it comes in. It also looked like the fuel pickup lines in the tank have been replaced before.

Seems like all the grey lines were already replaced.

 

[darren shumbo]

The little lines on the primer are directional...I think you have them backwards...Make sure the primer can actually suck fuel from the supply area to itself ! Make sure the supply line is clear as well as the line going to the carbs and that fuel can actually flow through the output line to the carbs and the little jet tube on the carb itself.

 

[POPPS]

In our race setup…our return line is at the bottom of the hull just to the side of the carbs,,the primer “t” is the lowest point of the return line…this way,,,the line is always full of fuel,,,and prevents any draw of air etc into the carb.

 

[Twigg1012]

For some closure on this.

The carb aparently is not stock, looks to be a 44bn after much research.

I replaced the primer + fuel selector, and the new primer was bad. Replaced again, current one primes but leaks at the plunger, good enough.

It'll run on the fuel from the primer but that is all.

Checking the popoff pressure, my needle and seat are leaking at 5 psi so I think that is the issue.

The primer was teed off the main line to the primer fitting on the carb(I know that Now)

Carb is getting fuel, so I am assuming the pop off is killing me.

 

[mikidymac]

The primer line never gets connected to the fuel line to the carb as they will almost always suck air at some point then the carb can't draw fuel.

As said above, only connect the primer feed line to a low point in the return line.