On the
Husqvarna K770 concrete saw, the fuel line routing can get a bit tight underneath the air filter base and manifold housing. [
1]
Here is exactly where each of the three lines connects on a K770 setup:
1. Main Fuel Inlet Line (Sucks Fuel to Engine)
- Routing: Connects the fuel filter inside the tank to the main metal inlet nipple on the carburetor body.
- How to trace it: This is the primary thick line coming straight out of the gas tank. Look closely at the Zama carburetor body—the main inlet is typically the larger brass/metal tube. If the saw runs but dies immediately or won’t start, this is the first line to verify. [1, 2]
2. Carburetor-to-Primer Suction Line
- Routing: Connects the second, smaller nipple on the carburetor directly to the suction side of the remote primer bulb assembly.
- How to trace it: On the remote primer bulb, the suction side is the shorter plastic nipple on the back of the bulb housing. This line acts as a bridge so that pressing the primer can draw air out of the carburetor's inner chambers. [1]
3. Tank Return / Purge Line
- Routing: Connects from the discharge side of the remote primer bulb back into the gas tank.
- How to trace it: On the remote primer bulb, look for the longer plastic nipple on the back. A fuel line attaches there and goes directly down into the gas tank through a second grommet hole. This line just dumps raw fuel back into the tank and does not have a filter attached to it. [1]
Quick Functional Check
Once you hook them up, press the primer bulb a few times. [
1]
- If routed correctly: The bulb will easily fill up with fuel and feel firm.
- If lines are crossed: The bulb will either flatten out completely and stay stuck down, or you'll see air bubbles persistently blowing backward into your main fuel filter line. [1]
