Overview & Key Details
The Graco 197318 Pump Cylinder is the OEM fluid-section cylinder (lower body) used on select high-capacity Graco pump lowers. If your sprayer uses a 250 cc lower, this cylinder is typically the correct replacement—be sure to confirm with your parts manual.
Compatible Machine
This part is used on systems equipped with a 250 cc fluid section (Dura-Flo 2-ball style). Check your model’s parts list to confirm fit.
- Graco GH 733 (Big 250 System)
- Graco GH 733 variants that ship with a 250 cc lower
- Graco NXT series air-powered pumps configured with a 250 cc Dura-Flo 2-ball lower
- Selected GH Big Rig units using the 250 cc lower (verify in the unit’s manual)
What is the Graco 197318 Pump Cylinder?
The cylinder is the precision-bored body of the pump’s fluid section. It houses the piston/packings and valves that generate pressure and flow. Replacing a worn cylinder restores sealing surface integrity, improving pressure hold, prime, and overall output.
Key Specifications
| Part Number | 197318 |
| Component | Fluid-Section Pump Cylinder (Lower Body) |
| Lower Size | 250 cc (Dura-Flo 2-ball style) |
| Typical Platforms | GH Big Rig (e.g., GH 733) and NXT series pumps built with 250 cc lowers |
| Fitment Tip | Match by model number, serial, and “250 cc” lower callout in the unit’s parts manual. |
When to Replace
- Chronic loss of pressure or slow build after packings are replaced
- Visible scoring/wear inside the cylinder bore
- Persistent leakback or poor prime that isn’t resolved by valve/packing service
Fitment Guidance
Because Graco uses multiple lower sizes (e.g., 145 cc, 180 cc, 220 cc, 250 cc, 290 cc), the correct cylinder must match your lower size and model generation.
- Confirm your sprayer’s exact model and revision
- Open the official parts list for your machine and locate the fluid section diagram
- Verify the cylinder callout: it should list 197318 for 250 cc applications
Frequently Asked Questions
Check your unit’s parts manual or nameplate details. In the fluid-section diagram, the lower size (e.g., 250 cc) and the cylinder part number will be listed. If it specifies 197318, this is the correct cylinder.
No. It fits models built with a 250 cc lower. Many GH/NXT variants use different lower sizes. Always match your exact model and lower size before ordering.
Often, yes. Inspect piston/throat packings, seats/balls, and seals. A full packing kit and valve components are commonly serviced together with the cylinder for best results.
Upgrades may require a matched lower assembly (cylinder, piston/rod, valves) and sometimes drive/ratio considerations. Consult the sprayer’s documentation before changing sizes.
If new packings don’t restore pressure/prime, or you see bore scoring and persistent leakback, the cylinder may be worn. In that case, replacing the Graco 197318 Pump Cylinder is advisable.
