APEXrtx06

Been dealing with/trying to figure this out for the last 18 months or so. On my starboard engine when I start it up I get a squeak at idle until things are fully warmed up (about 15 mins or so). I have replaced the belt, all idler pulleys, raw water pump, water circulating pump and alternator. Strange thing is, when I replaced the alternator it went away for a couple weeks, so I exchanged the alternator and replaced it again. Same thing, went away for a little while then came back. The only thing I haven't replaced is the power steering pump. Sick of throwing money at this. Any suggestions? I've tried the stethoscope method but still can't seem to pinpoint anything.

BUP

iTrader: (9)

What brand belt used here ? who sells it or makes it ?

wrong size ?

BELT TENSION ? has to be correct here

Misalignment

all pulley rotations - solid but very free spinning even when cold

power steering pump problem

water circ pump problem

what water circ pump did you use by whom and where did you buy it ?

Alternator who's ? where did you buy it ?

BajaDan

iTrader: (2)

I had the same problem but it was the alternator. Since it sounds like you have checked that and all other rotating devices, all I can offer is the old adage that just because it's new doesn't mean its good. I would still suspect the alternator bearings since that made a difference. If you remove the belt and spin it by hand (slow and fast) do you hear anything or feel any roughness at all? If you have a spare alternator laying around (and it sounds like you might) then I would not get another one, but take that to a local alternator/starter shop and have them replace the bearings, making sure that they have lubricant in them.

Good luck.

NightHawk

I fought this issue for a couple of years on my 496 Mag HO. I replaced all the same things you did. New belts, pulleys, a Hardin marine sea water pump w/ new bracket, rebuilt alternator. Nothing helped.

I then painted a mark on the belt and confirmed the squeak occurred for every one revolution of the belt. That lets out a lot of stuff including all the accessories. I finally used a small squirt of armor-all on the inside surface of the belt and the squeak quit instantly. It will come back in one or two outings so it gets another squirt. I do get a bit of belt dust so I run a K&N air filter and always carry a spare belt.