New Noise on 70 HP

Hello All,

When motor is warmed up, after running for 5-10 minutes over 4000 RPM a new sound is added in addition to the normal hum. It is like a rattle or ringing sound. It goes away below 3500 RPM and if I ***** for a while, it does not come back until the same warm up period has passed. It is a 1994 and runs great, still hits 5300 RPM and 34 MPH on Lund 1775, same as when new. Any suggestions?

Thanks for your help!

[robert graham]

Check under motor shroud on throttle and shift controls. My motor had a similar vibration/sound at certain RPM's and I ended up using some tie wraps to "tighten up" some of control cables/slides/etc. Good Luck!

Checked the lower unit, no water or milk. the linkage does have some rattle to it, but this is different. Any other suggestions?

[boats.net]

Check the motor mount covers, they may be loose. number 23 in this diagram Yamaha Outboard Parts 1994 70TLRS BRACKET 2 Diagram

Engine Noise

The noise could also be loose magnets on the flywheel,pull flywheel and check magnets and all components under and around flywheel.GOOD Luck