Low RPM rattle

[Andy Poletis]

I have a new 190 FSH, 1.8 l. Really impressed with the boat but have an annoying rattle at 2k rpm and lower. Goes away higher. I've tried to isolate, sounds like either exhaust or possibly a motor mount. Runs fast and no performance issues.

Taking it to dealer but I think you guys know it better than they do. Thank you.

 

[tdonoughue]

You may be right with the motor mount (I doubt exhaust--most of those would get louder at higher RPM), but with all annoying rattles in these boats I have learned to always check the impeller first. Some little stupid thing wrapped on the impeller shaft or stuck somewhere will cause all sorts of havoc, that may disappear at higher RPMs as the harmonics work out. Check in the cleanout plug and then from below (while on trailer). Others pull the jet easily; I have never had to in order to see or feel something stuck in there.

 

[Gym]

Could be impeller contacting the wear ring. Look for points of contact on the wear ring. You can also check for clearance with a flat blade feeler guage.

 

[Matt Phillips]

I have the same thing on my starboard engine. Port is smooth, but the starboar shakes and rattles....