RIVER RUNNING:
JET BOAT CARE FOR VALLEY WATER.

Valley water, Valley boats.

Jet boats have been built in the Lewiston–Clarkston Valley since the late 1960s, and local builders call it the Jet Boat Capital of the World. From the Valley, the Snake River runs up into Hells Canyon, where the Wild and Scenic section stretches from Hells Canyon Dam downstream to about river mile 180.

• Hells Canyon permits: The Forest Service requires a permit for every power and float boat launch in the Hells Canyon National Recreation Area, year-round. In the primary season (the Friday before Memorial Day through September 10), reserve on Recreation.gov; outside it, self-issue permits are at the launches. Parts of the Wild section have scheduled non-motorized days.
• Fueling on the river: HCNRA rules require fuel-absorbent material whenever you refuel on the river. Carry pads in the boat, not in the truck.
• Inspections and stickers: Idaho boats need an invasive species sticker, and every boater must stop at open watercraft inspection stations. Boats not registered in Washington need a Washington AIS prevention permit to launch there. Clean, drain, and dry between waters.
• Check the river: USGS gauges show current flow on the Snake River near Anatone and the Clearwater at Spalding, which is regulated by Dworshak Dam.

Permit rules: USFS Hells Canyon NRA Conditions of Use and the Recreation.gov permit page. Confirm current rules before each trip.

Look after the jet pump.

1. Grease the bearing on your unit’s schedule, with its grease.

Greasing intervals vary widely between jet units. One HamiltonJet manual calls for greasing the thrust bearing every 30 hours or monthly, whichever comes first. Tohatsu’s jet outboard supplement says to grease the driveshaft bearing before each use. Mercury’s jet outboard manual calls for extra grease after 30 hours to purge moisture. Use your unit’s manual, not a rule of thumb.

Use the grease the jet manufacturer specifies. Jet makers warn against general-purpose grease in this bearing; it needs to be water-resistant and match the specified consistency. Mercury notes that grease purging out dark, dirty gray is a sign to inspect the bearing and seals.

2. Check the intake, impeller, and anodes.

HamiltonJet lists the intake screen, impeller, and stator blades on its daily checks. Clear debris before you run, and look for rounded or chipped impeller edges. Replace sacrificial anodes before they are badly worn; that manual says when about two-thirds corroded.

3. Treat shallow water like it costs money.

A jet intake near the bottom “acts like a dredge,” in Tohatsu’s words, and pulling gravel through the pump rounds off and wears the impeller’s leading edges. Tohatsu advises more than two feet of water under the boat before getting on plane. HamiltonJet advises against high RPM at slow speeds in shallow water. Tilt jet outboards up when beached so the intake doesn’t fill with sand.

Jet references: HamiltonJet HJ212 manual, Tohatsu MD25/35B2 jet owner’s supplement (PDF), and Mercury Jet 65/80 manual. Your unit’s manual governs.

Rinse the river out.

Runoff-season water can carry a lot of silt. Yamaha recommends flushing an outboard after every use in dirty water, and the NMMA’s Discover Boating advises flushing outboards used in silty or muddy freshwater. Flush with clean water using the method in your engine manual, and keep the correct cooling-water supply running whenever the engine runs out of the water.

Rinse grit from the trailer, its bearings, and exposed grease points after launching in sandy or muddy spots. Check trailer bearings and hubs regularly; long highway tows to and from the river add up.

Flushing references: Yamaha Outboards and Discover Boating.

Engine oil and fuel for long upstream runs.

Running upriver means long stretches at steady, high load. Follow the engine maker’s oil and filter schedule for the hours you actually run, which may be the severe-service schedule, and keep a log of hours, oil changes, and grease service.

• Four-stroke gasoline engines: AMSOIL’s 10W-30 (WCT) and 10W-40 (WCF) Synthetic Marine Engine Oils carry NMMA FC-W Catalyst Compatible certification. Match the grade and specification your engine requires.
• Two-stroke engines: follow the engine’s injection or premix requirements. HP Marine Synthetic 2-Stroke Oil (HPM) is for compatible injection and premix systems. Never use crankcase oil as two-stroke oil.
• Diesel inboards: use the diesel oil specification in the engine manual.
• Fuel between trips: if the boat will sit for weeks, follow the engine maker’s storage guidance. AMSOIL Gasoline Stabilizer (AST) is made for stored gasoline, including ethanol blends; dose from the current label.

Choose the AMSOIL product for the job.

These are options to compare against your manuals, not a universal kit. Open each product page for current specifications, directions, sizes, price, and availability. Every shopping link includes Clearwater Oil dealer number 30575602.

Browse Clearwater Oil’s marine engine-oil catalog · Boat winterization guide · Printable boat checklist