420854358 Power Valve for Sea-Doo Speedster 800 1998-1999

Power Valve for Sea-Doo Speedster 800

This power valve is a replacement exhaust component that regulates exhaust port timing on 1998 to 1999 Sea-Doo Speedster 800 models, cross-referencing OEM part 420854358.

Overview

This power valve serves the exhaust system of the Sea-Doo Speedster 800, opening and closing the exhaust port to sharpen low-end response and top-end pull. The 420854358 power valve is built as a direct replacement for worn or seized original units on 1998 and 1999 boats. It suits owners and mechanics maintaining a personal watercraft engine.

Built For Performance

• OEM cross-reference 420854358 for straightforward replacement
• Controls exhaust port timing for improved throttle response across the rpm range
• Constructed to withstand continuous exhaust heat and moisture exposure
• Precision fitment for the 800 series Rotax engine exhaust housing
• Helps restore lost power when an original valve sticks or wears

Fits These Machines

• for Sea-Doo Speedster 800, 1998
• for Sea-Doo Speedster 800, 1999

On-The-Job Use

• Routine exhaust maintenance on 800 series Rotax engines
• Rebuilding a top end where power valve wear is present
• Restoring performance on a used Sea-Doo Speedster 800
• Servicing a boat that has sat unused and developed a sticky valve

Specs At A Glance

Good To Know

Q: Is this an original Sea-Doo part? A: This is an aftermarket replacement power valve cross-referenced to OEM 420854358. It fits the listed Sea-Doo Speedster 800 years but is not manufactured by Sea-Doo.

Q: How do I know if my power valve needs replacing? A: Common signs include sluggish acceleration, a stuck or rattling valve, and visible carbon buildup or scoring on the valve body. Comparing the old part to the 420854358 number confirms the match.

Slight variation in finish or dimensions may occur between production runs, and fit can depend on serial number, so confirm compatibility before ordering.