When installing a Sea-Doo 587, 657, 657X, 717, 787 or 787 RFI engine, your rotary valve must be timed. To do so requires a timing degree wheel, and the degree specification for your particular engine
’90-‘93 SP, ’91 GT, ’91 XP, ’93 SPi
115
’92 GTX, ’92 XP
129
’88, ’89, ‘94+ SP, '94+ SPi, ’90 GT, ‘93-'94 SPX, ‘93-'94 GTX, ’93 XP, '92-'96 GTS
130
‘95+ SPX, ‘94+ XP, ‘95+ GTX, '95+ HX, '96+ GTi, '97+ GTS, 1997+ GS
147
Place a screwdriver, pen, etc., or use a TDC gauge in the front (MAG) cylinder through the spark plug hole. Turn the crankshaft to find Top Dead Center of this piston.
Place a timing degree wheel over the rotary valve gear, aligning the 360° mark at the bottom of the front (MAG) intake port.
Find the timing spec for your particular year and model. Using the inside track of numbers, make a mark on the case corresponding to the timing spec for your engine. This will be somewhere around 11 or 12 o'clock on the case. NOTE: do not automatically use the notch on the case to time by - you NEED to make sure it's timed correctly.
Align the rotary valve as shown so that the port is open, and the edge of the valve matches as precisely as possible with the mark. NOTE: the valve is asymmetrical. Flip it around to find the closest match.
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