Drive Belt Problem - Help!

[tcat001]

I recently had my engine serviced (Mercruiser 3.0 Alpha 1 on a 1996 Bayliner 1850) and a new fan belt fitted - everything worked OK for one trip. On my next trip out there was a loud squealing noise and smoke from the engine compartment - after investigation I found it was the fan belt slipping. So - I tightened it and the noise stopped....for a while! Within 30 minutes the fan belt was again slipping but not because the alternator bracket had loosened.<br /><br />Can anyone let me know if you have experienced this problem and what the cause was....its driving me nuts!

 

[rodbolt]

Re: Drive Belt Problem - Help!

are you getting a lot of rubber dust? the most common cause of this is rusty pully sheaves. they will grind off a belt in short order.

 

[tcat001]

Re: Drive Belt Problem - Help!

Loads of Rubber Dust! I hope that this is the problem as it is an easy one to solve - I had bad visions of having to spend shed loads of more cash!!!<br /><br />My immediate though was that the two large pulleys were revolving at different speeds!

 

[Silvertip]

Re: Drive Belt Problem - Help!

Remove the belt and rotate pulleys by hand. If something is tight (alternator for example), the bearings may be tightening up which will cause belt slippage. Other repairs may be necessary here.

 

[MainstreetUSA1]

Re: Drive Belt Problem - Help!

If the problem is only rusty pulleys, you can remove the belts and pulleys. Get the rust off of the pulley surfaces carefully with a wire brush, steel wool, or fine grit sandpaper. Its important to do any sanding evenly so flat spots won't be formed on the pulley surfaces. Finish it up with a decent spray primer and durable glossy paint. Make sure the paint has cured up well before reinstalling the the belts on the pulley's.

 

[tcat001]

Re: Drive Belt Problem - Help!

The alternator was spinning OK but I did not try the other two pulleys! Which one is the drive pulley - the one at the top or the one at the bottom?

 

[Chris1956]

Re: Drive Belt Problem - Help!

Tony, If you take that worn out Mercruiser belt to an auto parts store, they may be able to match it up with the automotive version belt (1/2 price or less).

 

[MainstreetUSA1]

Re: Drive Belt Problem - Help!

The top pulley in the center turns the water circulation pump. The drive pulley is the one on center near the bottom of the front of the engine.<br /><br />

 

[180shabah]

Re: Drive Belt Problem - Help!

if you look for an automotive belt, make sure th angle of the V is the same. you may need to get a "race" use belt with a deeper V.

 

[tcat001]

Re: Drive Belt Problem - Help!

Thanks for all your help guys - this web site is amazing! My engine does not have the drive belt pictured above going to the left (the water circulation pump). I think my water circulation is pumped independantly. Does this mean that the drive belt only needs to go from the main drive pulley at the bottom of the engine to the alternator - or does the belt still need to go around all 3 pulleys?

 

[Haut Medoc]

Re: Drive Belt Problem - Help!

Not for the faint of heart but,.. I do my pulleys with the motor running. Use a pair of vice grips and a piece of #200 emery cloth or so. I do it by hand, but I woud never tell you that for fear of being drawn & quarterd by the "teachers'. Common sense & patience will be your guide. Never get your fingers anywhere near where you could lose a digit. Don't waste your time painting them, the best thing you can do is go boating often! ..J

 

[rodbolt]

Re: Drive Belt Problem - Help!

ohhhh ten million lashes to ya. however I have done the sandpaper trick myself. sanding and painting the rusty pulleys is temporary if it works at all. best to just replace them. if you must sand them have them bead blasted at a local shop. bead blasting wont remove good metal and will remove the rust. the motor in the above pic is a good example of a corrosion beast. looks as if the circulating water pump is or has been leaking. soon the timing cover will rust through and will leak oil. the motor in the above pic needs to have the circ pump pulley removed and the vent hole checked for signs of leakage. then it needs a careful cleaning and painting and a good coat of fluid film.

 

[Bewildered4toolong]

Re: Drive Belt Problem - Help!

I have a 1978 Fiberform Cougar , a 470 mercruiser in it, I have this same exact problem. The belt slips, smokes, Iv seen the alternator pulley get soooo hot it actually has melted a belt in two pieces at the Alt Pully. I have replaced the alt, used new belts, cleaned the wire connections and even installed a larger ground, to no avail... =( Just how tight should this belt be? The belt and pully get hot, smoke and really is driving me BatGuano!!! Any Suggestions?

 

[Bondo]

Re: Drive Belt Problem - Help!

Bewildered4toolong,......<br /><br />Welcome the the forums here at iboats.com......<br /><br />You'll get better results if you start Your Own thread on Your Issue............<br /><br />Even though some of Your symptons are like Tony-C's,.......<br />Your 470 is a Very Different Animal..........<br /><br />Good Luck.....

 

[Phantom17]

Re: Drive Belt Problem - Help!

Make sure you go by and thank the tech for stealing your money and not telling you your pulleys are bad too. Even if he's not in the business of cleaning instead of replacing, he could have said they looked rough to warn you, if that is the reason it shredded. Good service goes a long way, unlike your blt.

 

[Phantom17]

Re: Drive Belt Problem - Help!

sorry, "unlike your belt"....damn keyboard doesn't work with these fingers.......have to get new fingers