loud rattle 2008 250proxs

[crawpytime1]

i hear a loud rattle coming from the motor at different RPM's. It sounds like something is loose and is jumping around in the housing. The motor has always ran great. I have spoke to others and they say the have heard the same noise in other boats with the 250 pro xs. Any thoughts would help>

[jettdog68]

its standard deal on tghe pro XS motors, usually arounf 3500rpm. Dont worry about it!!!

[chris20]

Yep we have an 2003 250xs and it does the same thing since new

[EuropeanAM]

Although there IS a "known harmonic resonance" in these engines (between 3000-3500 RPM range)... any time a difference, or "concerning sound" is noted, it is wise to check for anything "loose" on the engine:

Possibilities include (but are not necessarily limited to):

-Engine mounting bolts
-Steering Hardware
-Hood Latches
-Anode Plate above prop
-Side Mounted Anode Plates
-Plastic Lower Mount Covers
-Belt or tensioner
-Air compressor pulley (or compressor itself)
-Anything "loose" and not properly torqued on the engine.

We have had good results "lessening" the transfer of harmonic vibration (when mounted to an aluminum jackplate), by simply adding a 5/16" bead of 3M 5200 sealant to the engine mounting brackets before installing engine (then torquing mounting bolts to 80 ft. lbs).

We retorque jackplate and engine to jackplate mounting bolts AT LEAST once per year, or every 100 hours (whichever occurs FIRST).

Also- see the following post:

http://www.bbcboards.net/zerothread?id=615708