How to Replace the Jet Pump Impeller on a Sea-Doo Sportster?
My 2012 Sea-Doo Sportster is revving high but struggling to get on the plane, and I suspect the impeller is chewed up. How do I go about replacing the impeller, and what special tools or sealants do I need to get the job done properly?
Answer
Replacing the jet pump impeller on a Sea-Doo Sportster involves unbolting the pump housing from the transom, using a dedicated splined tool to break the old unit free, and threading on the replacement. You should always replace the plastic wear ring at the same time, as fitting a new impeller inside a scored ring will not cure cavitation or restore lost top-end speed.
Diagnosing the Fault
Before turning a spanner, confirm the impeller needs replacing. High engine revs combined with a struggle to get on the plane point to cavitation. Stones or debris chew up the leading edges of the impeller blades and score the wear ring. Disconnect the battery before working near the jet nozzle to prevent accidental engine cranking.
Gather a metric socket set (10mm, 13mm, and 17mm), a bench vice, a heavy-duty breaker bar, and a heat gun. You must buy an impeller spline tool. For the 4-TEC engines found in 2012 Sportsters, a Solas WR011 or the BRP OEM equivalent grips the impeller splines without causing damage.
Removing the Jet Pump
Start at the transom. Disconnect the steering cable and the reverse gate linkage. These parts use 10mm bolts and nyloc nuts. Keep the plastic bushings safe because they drop out easily.
Remove the four 13mm nuts securing the pump housing to the transom plate. Pull the entire pump assembly straight back to slide it off the driveshaft splines. If the pump sticks, tap it with a rubber mallet to break the factory silicone seal.
Shine a torch up the driveshaft tunnel and inspect the carbon seal. A chipped seal or weeping black soot means you need a replacement. Changing the seal requires pulling the shaft from inside the engine bay.
Removing the Old Impeller
The factory impeller uses high-strength threadlocker and requires serious heat to budge. Remove the three bolts holding the plastic nose cone onto the front of the pump housing. Pull the cone off and drain the jet pump oil into a pan.
Clamp the flat edges of the rear impeller shaft in a bench vice. Insert the impeller removal tool into the front splines. Apply a heat gun directly to the base of the impeller for 3 to 5 minutes to melt the factory Loctite.
Attach a long breaker bar to the spline tool and turn it anti-clockwise. Apply steady pressure. Expect a loud crack when the threadlocker lets go. Spin the old impeller off the shaft.