Mercury 125 new noise

[Skinner123456789]

I have a 2001 Mercury 125 on a 17' 1" Champion boat. I have ran this boat with no problems until I put it in the shop for a recalled trailer issue. While it was in the shop I told them to refinish the prop for me (I asked if they could get alittle more speed out of it) I use to run about 4900 rpms WOT, 52-53 mph. This was the 1st day to run the boat for me and it was running about 5100 to 5150 rpms WOT with the same 52-53 mph, I was watching the tach so much that I might be running to many rpms I sudenly look at the Speedometer and it read 45 mph. well I didnt think to much about it till I came up to my fishing hole on idle. My partner and I noticed a whinning noise so I took it out of gear and it had the same noise. (Like some thing was grinding or rubbing in the engine) I stoped and fished for a while so it cooled down. Started it up and it sounded fine made it to the boat ramp and it started it again. I loaded it on the trailer and checked to see if the lower end was hot but it wasnt. Does any one know the max rpm for a Merc 125, I think it is 5250 but not sure. Could this noise be related to the prop work or just concidental and something else. <br />Thanks for all your help in advance<br />Steve

 

[Josh Knapp]

Re: Mercury 125 new noise

on your 2001 it may be new enough that it says on the serial number sticker on the transom clamp bracket. it may not be new enough. mercury started doing that recently but I am not sure when they started.<br /><br />josh

 

[Mettaree]

Re: Mercury 125 new noise

Josh: On my '96 200hp WOT is listed on the transom bracket as you say.<br /><br />

 

[quantumleap]

Re: Mercury 125 new noise

Yes, the WOT RPM range is 4850-5250. Check for clearance between the prop and lower unit. Check to make sure the thrust washer is installed correctly. What pitch prop are you running?