How to Diagnose and Repair a Broken Lawnmower Fuel Line. The fuel filter is replaced and the mower checked for proper running. This repair is continued from How to Diagnose and Repair a Broken Lawnmower Fuel Line – Part 3.

Replace the Lawn Mower Fuel Filter

After replacing the broken and cracked fuel lines inside the gas tanks, I replaced the fuel filter for preventive maintenance. The fuel filter is located on the right front side of the engine. The fuel hoses are secured to the filter by two hose bands.

Fuel Filter - Gravely ZT1640 Lawn Mower

Fuel Filter – Gravely ZT1640 Lawn Mower

The old and new fuel filters are shown in the following photo. The black bits of dirt are on the outside case of the old filter. I purchased the new filter from my local Gravely dealer for about $4.

Notice the arrow imprinted on the case of both filters indicating the direction of fuel flow. The filter is installed with the arrow pointing towards the fuel pump.

Old and New Fuel Filters

Old and New Fuel Filters

Remove the old filter by releasing the hose band with a pair of pliers and slide the bands an inch or so down the hose. Pull the hoses off and remove the old filter.

Install the new filter by pressing on the hoses and fasten with the hose bands. Take care to install the filter with the arrow on the filter housing pointing towards the fuel filter.

New Fuel Filter Installation - Gravely ZT1640 Lawn Mower

New Fuel Filter Installation – Gravely ZT1640 Lawn Mower

Restart the Lawn Mower Engine

The engine stopped running because the intake fuel lines inside the gas tanks had deteriorated and broken off. The fuel lines, fuel filter and carburetor were bone dry when the engine quit due to fuel starvation. This is the first time starting after installing new fuel lines and all the lines are dry.

To restart the engine:

  1. Set the fuel selector/shutoff valve to the RIGHT tank (because it’s closest).
  2. Set the throttle position to Full Choke.
  3. Had a helper turn the starter key ON while watching the fuel filter. Gasoline was flowing through the fuel filter in about 3 seconds. The engine started after another 2-3 seconds of steady cranking. I set the throttle to Fast Run and the engine ran smoothly.
  4. I let the engine run a couple of minutes on the right tank, then set the fuel selector the left tank. I saw a few air bubbles in the fuel filter and the engine continued to run smoothly on the left tank.
New Fuel Filter - Filling with Gas and Engine Running

New Fuel Filter – Filling with Gas and Engine Running

The fuel level in the fuel filter dropped some with the engine running on full throttle. The engine continued to run strongly. After 10 minutes or so, I drove the mower up and down the hill and mowed some grass. Everything was fine.

Engine Running after Replacing the Fuel Lines and Filter

Engine Running after Replacing the Fuel Lines and Filter

Engine running after replacing the fuel lines and fuel filter.

Gravely ZT1640 Lawn Mower - Engine Running

Gravely ZT1640 Lawn Mower – Engine Running

I reattached the engine hood and am now ready for the rest of the mowing season.

Gravely ZT1640 - Engine Hood Re-Installed

Gravely ZT1640 – Engine Hood Re-Installed

The total cost of this repair was $36 for parts from my local Gravely Dealer and about 1.5 hours of my time. The first hour was spent diagnosing the fuel starvation problem and 30 minutes to remove and install the new parts.

Hope this helps,

Bob Jackson

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