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New to the forum and hoping for some suggestions as to the possible cause of an unusual noise that I have experienced for the past year in my 2004 250 HPDI. It sounds like a loose chain on a chain saw when running above about 3000-3500 RPM. The engine runs normal besides the noise. I'm sure there is no chain anywhere in the engine so I am stumped.
I have changed the HP pump drive belt and idler as well as fully serviced lower unit and water pump by Yamaha tech. All bolts on engine and jack plate checked, nothing seems loose that could be vibrating.
Wondering if it could be in the cooling system somewhere like a loose anode or thermostat.
Any help would be appreciated.
I have changed the HP pump drive belt and idler as well as fully serviced lower unit and water pump by Yamaha tech. All bolts on engine and jack plate checked, nothing seems loose that could be vibrating.
Wondering if it could be in the cooling system somewhere like a loose anode or thermostat.
Any help would be appreciated.