Alternator Belt Failures

[Stank]

I have a 1994 OMC Cobra 5 ltr. engine in a Four Winns 238 Vista. The alternator belt is constantly<br />breaking after only a few hours of operation. I've<br />checked all the obvious things that would cause this to happen but cannot find the actual cause<br />of the problem. I changed the alternator but the<br />belts are still breaking. Does anyone have any<br />ideas or suggestions?

 

[flashback]

Re: Alternator Belt Failures

I saw one one time that the harmonic balancer (pully that is on the crankshaft) had some rough burrs on it and it was eating up the belts.. Do you have any black rubber dust in the area of the belt, also check the alignment of the belt, are all the pulleys in line?

 

[daveswaves]

Re: Alternator Belt Failures

Assuming your alternator spins freely when the belt is off, you either have the belt too tight, a bent or misaligned pulley, or burrs or cracks in the pulley.

 

[johnkc]

Re: Alternator Belt Failures

hello , do you have a constant, heavy load on the alt. like a dual battery switch and running it in the all position all of the time ? and are you using oem belts or auto belts?

 

[russthemuss]

Re: Alternator Belt Failures

Make sure the belts are the right 'section' and both pully's are the same section ie A,B,C Pully's cant be worn.Run you finger in the v and check its still a v (With the engine off!!)

 

[Stank]

Re: Alternator Belt Failures

Thanks for the quick responses. I cheked all the pulleys and belt alignment. All are ok. The belts<br />being used are what was on when I bought the boat new. johnke's suggestion about the excessive load on the alternator is interesting. When the belt does go it hapens very quickly when I'm under way, never when docked and idling. When looking<br />at the wear on the belt it appears that the alt. pulley stops momentarily but spins free when I check it after the belt falls off. Any suggestions on how to check on an overload condition?

 

[johnkc]

Re: Alternator Belt Failures

do you have something in the boat that is using a lot of amps , such as stereo amplifier, windlass,big blender for the margaritas,power inverter, etc?even a dual battery switch in the all position will put a heavy load on the alt.try a different battery ,maybe a short in the battery. also have you checked all of your pos. and neg. connections on the engine and battery,corroded/loose connections will cause high resistance thus high alternator amp. output . {edit, but the fuse would probably blow if some thing was pulling too much amps. from the alt} when you say it looks as if the alt stops for a second then turns freely have you considered the water pump pulley stopping instead? good luck

 

[ebbtide176]

Re: Alternator Belt Failures

good luck, sounds like you've got some leads to check on already. all i can add is that there are only a few situations that can cause your problem, and you've got some starting points already.<br /><br />get someone else to drive and watch the motor for details, is the belt slipping off the pulleys or shreading?