are you referring to the power valves?? they open the exhaust ports and give the engine more hp, however they need clips added to prevent them from dropping in to the cylinder and wrecking the rings.
it's going in for a check up, just for kicks, 112 hours. they want $550 to install the clips, and we don't even know if they have been installed before.
I think you can go to www.yamahajetboaters.com on the 2 stroke section and find people who have done the clips and get them to tell you how it's done, or how to see if they have been done, but without the pv clips, the valves are known to cause the engines to hatch
