When matching a Sierra marine fuel/water separator, identify the spin-on element as well as the mounting head. These four kit numbers include two filter lengths and two different micron ratings. The original filter number is often more useful than the outside paint colour when selecting a correct replacement.
First compare the filter height and number
18-7848-1 and 18-7983-1 use short elements. The 18-7852-1 and 18-7982-1 are tall styles. Check original filter clearance before swapping.
The published kit number identifies the filtration rating. Do not fit a coarser or finer element without confirming the engine's requirements.
Sierra part-number identification
Manufacturer kit specifications are shown in the chart below. The replacement element number is listed separately so a replacement can be checked against the original.
| Kit MPN | Micron rating | Filter height | Spin-on element | Head MPN | Head ports |
|---|---|---|---|---|---|
| 18-7848-1 | 21 micron | Short | 18-7844 | 18-7853-1 | ¼-inch pipe threads |
| 18-7852-1 | 21 micron | Tall | 18-7845 | 18-7853-1 | ¼-inch pipe threads |
| 18-7982-1 | 10 micron | Tall | 18-7945 | 18-7853-1 | ¼-inch pipe threads |
| 18-7983-1 | 10 micron | Short | 18-7944 | 18-7853-1 | ¼-inch pipe threads |
Check the threaded head, not just the hose
Remove the model from the original filter label and confirm the mounting head before ordering. A Sierra 18-7853-1 head has ¼-inch threaded pipe ports, which is not the same thing as a ¼-inch hose-barb connection. Inspect line adapters and the fuel-system routing.
The numbered kit includes a filter and a mounting head according to Sierra's catalog. A replacement spin-on element alone does not include the head or pipe plugs.
Before refitting a separator
Inspect the head and filter seating, corrosion, brackets, hose fittings and space to remove the spin-on element. Confirm fuel compatibility and installation position from the engine's instructions. Service the assembly only with the fuel system safely isolated.
Confirm whether the existing engine calls for 10- or 21-micron filtration. Do not infer compatibility solely because the filter screws onto a similar-looking head.
Open the exact Sierra kit listing
Select a matched MPN to review the saved product listing and current availability.
Sierra 18-7848-1
Recognize the short 18-7844 filter on an aluminum 18-7853-1 head; 21-micron kit.
Review matching listing
Sierra 18-7852-1
Uses the taller 18-7845 element; the 21-micron rating matches 18-7848-1 but height differs.
Review matching listing
Sierra 18-7982-1
Identify the tall 18-7945 replacement element. The kit is not interchangeable by appearance alone.
Review matching listing
Sierra 18-7983-1
Uses the short 18-7944 element and 10-micron filtration instead of a 21-micron element.
Review matching listingRelated marine filter identification
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