View Full Version : Noise from the alternator

Jeff d
07-05-2011, 12:03 PM
2000 230 VRS w/ LTR and 324 hrs.

Took the boat out yesterday and on our 3rd wakeboarding set when I stopped to pickup a rider I heard a slight buzz coming from the engine compartment. I popped the sundeck up and it was decently loud and more of a rapid clicking than a buzz. it sounded like something was contacting the star wheel for the crankshaft position sensor or the fan on the alternator. It was not how I would expect something loose that was just oscillating/vibrating to sound. This occurred while at idle or in gear and increased in frequency as the RPM of the engine increased.

I had to drain the ballast to get a closer look because I can't fold down the engine compartment dividers with the rear bags full. I shutdown the engine and waited for the bags to drain. I started it back up and let the wife putt around for about 10 minutes while I got intimate with the engine. It was definitely coming from the alternator area but I could not be certain that it was the alternator itself as it was loud around there. I could "feel" the vibration in the alternator, tensioner and alternator bracket but not in the engine block, water pump, etc. I saw nothing contacting the fan blades on the alternator like I was hoping to find. The volt meter showed a constant 13 volts and it continued to run fine with no noticeable drop on the gauge.

I shut the engine down again and let the kids swim for a while. Started it back up about 20 mins later and the noise was gone. Ran it at just above idle for about another 30 minutes and the noise was gone. The alternator seemed to continue to charge the system fine.

I may replace the tensioner as it's available from O'Reilly for $40 and couldn't hurt since I'd be willing to bet the one on there is original (i.e. 11 years old):

I'd rather not spend $300 on an alternator if that's not the problem though. Doing a little out of town boat trip at the beginning of next month though and don't want it to fail then.

Has anyone seen/heard an alternator fail in this manner? I've had idler pulleys scream when bearings failed and alternators just stop charging but never a buzz/rapid click like this.

If I have this rebuilt do they typically address these sort of mechanical (bearing/bushing, etc) issues or just rewind it and clean it up?


Jeff d
07-05-2011, 03:31 PM
I talked to a guy at a local alternator/starter shop and before I even started to tell him what problems I was having he mentioned that the style of Leece-Neville alternator that I have has a reputation for the housing bolts backing out when they get old.

This is exactly what it sounded like. I'm betting that when I take a look at the alternator tonight I will find a loose bolt holding the housing together that protruded out and made contact with the fan blades. It probably either wore away a groove in the back of the fan or got knocked back into the housing and the noise stopped.

Jeff d
07-05-2011, 10:58 PM
Well, my bolt theory was not really feasible when I looked at the alternator unless someone managed to install a bolt that was too long.

I removed the belt and spun the pulley around and there was a mangled fin on the fan. Not sure what happened. It looks like it contacted something but there's nothing in close enough proximity. My only guess is that based on how ugly and rusty the alternator is that a part fell out of the inside of it into the fan.

It still works but I might go ahead and replace it before the trip in an attempt to avoid any problems on the trip. I'll take the opportunity to go to a 90 amp (This is a 51 amp) or so to accommodate my long term plans to add a 2nd battery and a 5 channel amp.

07-17-2011, 10:40 AM
"I may replace the tensioner as it's available from O'Reilly for $40 and couldn't hurt since I'd be willing to bet the one on there is original (i.e. 11 years old):

Thanks for the number. Lost my belt yesterday. I'm taking your advice and replacing the tensioner.

Jeff d
07-17-2011, 11:47 AM
FYI Other part stores had an equivalent tensioner for like $8-10 less but they had plastic pulleys. Oreilly was the only place that I found that stocked one with the metal pulley.