Serpentine Belt Freying... Again
 

i have heard there was a recall from merc on the 502 mags serpentine pulley system, but of course, i never got a notice, and never had a problem until the end of last year. I have under 200 hours on the boat still, so its really looks like brand new condition still.

My serpentine belt on one motor keeps slipping rearward at the tensioner pulley and it keeps freying the serpentine belt. I replaced the tensioner pulley and got a new belt, & it still did it, then i replaced the tensioner bracket, and another tensioner pully & belt, & it still did it, and im still having this issue, and going thru belts, and cleaning the dust off my motors every time i use the boat which really sucks, cuz im kind of a clean freak. So who knows what the fix is cuz it's really annoying me. I've checked all the accesories, all the bearings are fine in all of the components. i run a straight edge across them, they all line up just fine... Now that i have heard this was a common issue and that there was a recall, i want to hear who knows something about it, and who i call, or what i need to buy to stop this once and for all.... Thanks in advance.
Rob

ttt

I have yet to see a serpentine belt that did not leave residue. On a boat it slings all over the engine compartment and in a car there is more air flowing through and open area that allows the residue to escape.

there is a bushing that i replaced in the wheel that stopped it on mine

i'm guessing you mean the bushing in the tensioner? i've replaced the entire tensioner bracket assembly, which included the new tensioner and the bushing? Still looking for an answer? I use the boat once, and the belt totally freys, and is about to lose one of the four bands in it... HELP!!

ttt again... ;)

We had problems with the serp belt on the race boat but this was not a 496. Anyhow we checked the allignment and installed a spacer on the water pump pulley and started running a gator belt. No problems since. Check your allignment. Check for burrs or rust on the pulleys and switch to a gator belt. Dave

Ditto Dave!!

Julie

ahh finally some replies, thanks! It's a 502Mag EFI, but the point i'm at it leading me to think the tensioner pulley needs to go rearward about 1/8"-3/16" which means i need to take the bracket off and machine that much off of the back side of the bracket where it mounts to the block... the pulley doesnt have much clearance room to move rearward on the bracket by shortening the spacer, so i will have to modify the bracket.

What a P.I.T.A. this belt thing is!!! :blaster:

ok, i got my answer... In January of 2000 Mercury put out a parts bulleten for all V6 & V8 sterndrive engines with a serpentine belt. It's Bulleten 98-1 that was for the power steering pulley to go from a 4 3/4"dia plastic pulley, to 5-3/4" dia. metal pulley. it says to order a belt/pulley kit... Bigger pulley, & a longer belt... Problem solved, and now some archive reference for the future...

My pully and belt came yesterday, so i tow the boat down the street to my uncles marina to put it on and make his trained eye look at it, and my uncle hops in there and says "you have the 5 3/4" metal pully..."

So i ordered a pully i didnt need... Jacka$$. So he's checking everything out for alignment,which looks good, then he pulls the belts off both motors, and says, "order an alternator, This one doesnt sound like the other one, and at rpm, it could be locking up" Then comparing the paint i n the grooves for the serpentine, the suspect alternator has the paint rubbed off and the other one looks fine. All the other pullies on that motor have shiny paint on them, so thats my theory today!

When i spun everything, and everything spun fine, and looked fine, but when you compare one alternator to the other, they sure dont sound the same... I guess i should have tried that...

So the new alternator is there now, gotta go put it on... 2 bolts, 2 screws, and 2 plugs... Not so bad. Lets hope thats all it was. Lesson learned, check the motor thats 2 feet away and compare, compare, compare...

I didn't know your Uncle owned that marnia. I saw your boat there yesterday and almost stopped to say hey but it was ready to rain and I need to get home to put the cover on the phantom.

yeah thats him, he's been there for a long time now...Definitely good people. He bought that before i moved out there and its been over 10 years that i've lived there now!! Where's the time go?

After rearranging all the boats in the yard, I got it backed it inside just before the rain set in. He's been a marine mechanic since he was a kid, his dad was a marine mechanic, and he fell into it from the time he was old enough and usefull enough to desipher a 5/16 from a torque wrench~! Lol
He's in his 50's now,so he's definitely knowledgeable, so theres alot of years under his belt. I'll be up there tonight too putting the alternator and belt on if you want to stop in and laugh at me for not checking that first! i'll have a black tahoe parked out front. I'm hoping not to be there long though! ;)

Edit:

Actually i'm hoping they already have it done when i get there! I try to do everything i can on my own, i know they are always busy, and i hate to bug them, but it always seems to be better to let him take a look Lol No matter what it is, he's usually seen it before...

just curious if the alternator swap solved the problem----

yeah it worked. i was out saturday and sunday, and it was fine. What a relief that is.

Since you got it fixed.......

I was going to say that some thing must be out of alignment.

I had a car that shredded a serpentine belt after 60K miles. Replaced it, shredded that one the next day. Replaced it again and promptly shredded that one. Started looking as to why and noticed the water pump was out of alignment. Couldn't find anything bent or broken till I noticed that the pully was mounted backwards. I have never taken the pump apart or off since new. The pully was mounted backwards at the factory. Why the original belt lasted so long is a mystery to me.