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496mag
07-08-2001, 10:37 AM
I recently purchased a new boat with a 496 mag. At approx. 3.5 hours the serpentine belt broke. Brought the boat to Mercury Marine rep. & a new belt was installed. At approx. 8 hours the belt was thrown off the pulleys. Brought the boat to Mercury Marine rep. again & they found that one of the pulleys was out of alignment 1/8 of an inch. With approx. 28 hours the belt was thrown again. It is currently at the Mercury Marine rep.shop again,third time.
Does anybody know of any simuliar problems with the 496 mag ?

FIREMAN
07-09-2001, 09:36 PM
I had the same problem at about 20hrs. Sy from Commander sent a driver to Vegas to pick the boat up and fix it and offered to do the 20 hr service for the trouble. 5 day service driveway to driveway. The pulley was out of alignment by 1/8 of an inch. Running strong ever since and haulin the mail. I have the Mag HO
Dusty
[This message has been edited by FIREMAN (edited July 09, 2001).]

ULTRA28
07-09-2001, 09:38 PM
Now thats what I call service. Sy is a great guy and it goes to show you how much he cares about keeping his customers happy.

sea buddy
07-19-2001, 05:04 PM
Have been on two that have belt whine and another had a bad fuel pump.

jet496
07-23-2001, 03:47 PM
I have over 70 hours on my new Ultra 21 Stealth with a 496 HO. No problems yet. Runs like a champ.

FIREMAN
07-24-2001, 07:50 PM
Up to 36hrs and Still running like a champ.
Glad as hell that I got the mag HO too.
It hauls the mail...

Maelstrom 23
07-24-2001, 10:56 PM
FIREMAN:
Which pulley was out of alignment ?
There are a few on front of the engine !
Did you notice any black dust from the belt before it broke ?
Part of the hatch and engine on my boat is covered with black dust (not much but makes me wonder) from the belt, warning sign of bad times coming ?
SEA BUDDY:
Did the belt whine occur at low or high rpm ?
I have some strange whining noise at 2-2500 rpm on my 496HO, could that be the belt ?
Other than that it's a great engine, mine just broken in with 10hrs.

496mag
07-25-2001, 05:39 PM
Originally posted by Maelstrom 23:
FIREMAN:
Which pulley was out of alignment ?
There are a few on front of the engine !
Did you notice any black dust from the belt before it broke ?
Part of the hatch and engine on my boat is covered with black dust (not much but makes me wonder) from the belt, warning sign of bad times coming ?
SEA BUDDY:
Did the belt whine occur at low or high rpm ?
I have some strange whining noise at 2-2500 rpm on my 496HO, could that be the belt ?
Other than that it's a great engine, mine just broken in with 10hrs.
Idler pulley was out of alignment on my motor (496mag) . Did not notice any black dust, belt broke with 3.5 hrs.. Third time at Mercury Marine rep., they replaced alternator & bracket assembly, said it was out of alignment. Will be taking it to Havasu this weekend to see if it works.
[This message has been edited by 496mag (edited July 25, 2001).]
[This message has been edited by 496mag (edited July 25, 2001).]

FIREMAN
07-26-2001, 09:17 AM
I believe it was the idle pulley. It's the only one that is plastic. The rest are aluminum or steel. It's a recall that is supposed to be taken care of before you take ownership. But there is a shortage of the little things as every engine needs one. No big deal to fix and by now it shouldn't take long to get one as it was 2 months ago when they noticed. I did notice that the side closest to the front of the hatch of that belt in question was shaved down a bit, probably from being out of alignment. I got my rocket back 20 hrs ago, have been runnin it hard and no furthers problems. Infact I stand by the 496 mag HO. It hauls the mail...
[This message has been edited by FIREMAN (edited July 26, 2001).]

sea buddy
07-26-2001, 04:26 PM
Fuel pump was the whine, then a intermittent falling back to idle or 2,000 rpm's, then it quit. About 4 engine hours from 1 st to last.

h2otech
08-08-2001, 07:11 PM
[In my dealings with the 496 the black dust is probably comming fro the delt making contact with the clamp that holds the heat exchanger in place, or your water pump bracket is distorted.

James'SS-24
08-11-2001, 08:24 AM
I Have noticed the black dust in my engine compartment and I have been keeping a close eye on the belt. It doesn't seem to be fraying yet. 35 hours on mine so far but I am having fuel starvation problems. The local mercruiser dealer can't even look at it until next week (maybe) he says :ROLLEYES:

AWelsh
08-30-2001, 03:12 AM
I also have a new boat with a 496mag, at approximately 20 hours I noticed black bits of rubber all over the engine compartment. Brought the boat in for its 20 hour service and told the service manager my serpentine belt was disintegrating. The service manager called yesterday said the boat was ready. He said that the serpentine belt "problem" was a normal part of the break in process. I'm afraid to take my boat on the water. I don't want to get stuck in the middle of the lake with a broken belt. Does anyone have an updates on this strange problem?

AWelsh
08-30-2001, 05:28 PM
James'SS-24, can you update me with any changes in your situation? I too have the "black dust" problem. I'd appreciate any responses.
Thanks
AWelsh

James'SS-24
08-30-2001, 06:38 PM
I checked everything over really close as far as pully alignment and the possibility of something rubbing the belt but I can find nothing wrong. The belt itself is showing no unusual signs of wear so I intend to keep running and just keep an eye on things. About every ten hours I clean the dust from engine compartment. My theory is that the belt has to make so many turns that it is wearing more than I'm used to seeing. Another thing I've thought of is with a similar setup on a car the dust can get out of the engine compartment were as in a boat it can't. I did get my fuel problem fixed. I wound up doing it myself. Turns out there is a screen in the inlet of the transfer pump that was plugged with dirt, metal shavings, and even a bug! To date this is the only problem this engine has given me. http://free.***boat.net/ubb/wink.gif

James'SS-24
08-30-2001, 06:42 PM
The season's almost over now but next season I will carry a spare belt! 36 hours so far without a belt problem http://free.***boat.net/ubb/biggrin.gif

AWelsh
08-31-2001, 02:52 AM
Thanks for the reply James'SS-24. I guess I'll need to pick up a spare belt also. I still have the feeling my belt is going to break, there is just to much of the black bits of rubber in my engine bay. I even had little slivers of rubber about 1/4 to 3/8's inches long scattered on both sides of the engine bay.

James'SS-24
08-31-2001, 02:33 PM
Wow! Mine has never been any more than a fine dust about the consistancy of sand. In another post I read where some one found a clamp on the heat exchanger rubbing the belt. Maybe check that. All of that stuff is really close. http://free.***boat.net/ubb/eek.gif