2.5 mercury clutch rattle

[sxmerc]

I've got a 200 2.5 carb Merc, spinning a 17 pitch Mirage Plus. She's got a wicked case of idle speed clutch rattle, and I'm looking for some suggestions to shut it up, before I go nuts. Help.

[Digger Dave]

Check your flywheel hasn't come loose. I had one come loose and rattled at idle.

[sxmerc]

Just had the flywheel off and then back on and torqued back down to spec, for stator replacement, so I know that's not it. My buddy has a 2.5 175 EFI spinning the same prop of a different pitch, and he's got that same clutch rattle. I'm gonna' try a flo torq III hub tomorrow eventhough I know they're only rated for up to 115 hp. Just trying to see if anyone else out there had experienced this same thing, and maybe had a different take on it.

[Greg Moss]

shift cable adjusted correctly?

[sxmerc]

Yes cable is adjusted correctly. Rattle is only at idle. Bumping up throttle about 200 to 300 rpm and the rattle goes away. I know this has been a problem with alot of the Merc motors in the 115, 90, 75 range, especially the four strokes, while swinging a stainless wheel. For the record, this rattle does not exist with my spare aluminum prop. There is actually a service bulletin from Merc on those Mid-range motors, talking about this issue.

[Greg Moss]

Well your not asking about mid range motors. If you got clutch rattle in a 2.5 200 you got the cable adjusted wrong or there is something inside the lower unit wrong.

[TEXAS20225]

on a v6 merc lower ?. i rebuild lots of these lowers and i cant honestly say that i have ever heard one rattle . except if the cables are not adjusted right and the dog is ticking the lugs on either forward or reverse gear

[donmac]

I have experienced the same noise running large solid hub 32 cleavers, i assumed it was because the motor was lugging that wheel.turning the idle up worked for me as the boat was only raced and not pleasure used. twisting a 17 shouldn't lug your motor,check the timing.

[sosmerc]

The flotorq III will help.

[sxmerc]

Problem solved. Found #5 plug cold after about 20 minutes of idling. Carb had some contaminates plugging idle circuit. Cleaned and rebuilt carbs, idles nice with no more rattle. Isn't it amazing what results you can get when you're not being an idiot?