I have an upgraded 75 amp Balmar alternator on my Westerbeke 27A. I am having trouble with the belt slipping and “squeeling”. I have tightened the belt and it seems to hold. I have used belt dressing that seems to help temporarily. The problem is most persistent at start up when the alternator out put is greatest. If I keep rpms low–1500-2000–the squeal won’t happen, and will often abate altogether after running at lower rpms for a while. The 3/8 inch belt is new and the pully is clean.
I’m thinking the problem may be caused by an undersized belt. The Balmar manual says it can take a 3/8 or 1/2 belt. But can the engine pully? Any thoughts would be appreciated.
First, use a straight edge to make absolutely sure your pulleys are in alignment. I’m not sure about a pulley accepting two different size belts. I would favor the belt size for the W-27 engine pulley. Remove your belt and place it in the groove of each pulley and make sure it fits correctly. With the belts squealing, carefully spray each pulley (one at a time) with a little water to find out which one is making the annoying noise. I’ll bet there is an online video on this subject.
Good luck,
Joe Valinoti
S/V IL Gatto NS30U #221
Sea Harbour YC
Oriental, NC USA
PS – I’ve owned a VW/Porsche/Audi garage for 32 years and can’t get my 89’ Vanagon to stop squealing. Not finding a permanent solution is most annoying.
For what’s it s worth I had a similar problem with m NS 36 for a couple of years . Changed belts ,went to stronger belts till some one suggested I the wire from alternator to a higher gauge . Put heavier wire and problem solved. The alternator experienced higher resistance trying to charge batteries .
I may have solved my belt problem, although I only have a couple of hours without “squeal” and accompanying erratic tach readings. First, I tighten the belt using a belt tightener at the longest run. I changed the belt load setting on my Balmar ARS-5 regulator from 1 to 3. Knock on wood, but this seems to have done the trick. I was led to this by the fact that sometimes after running the engine for a while at low rpms to avoid the squeal, I could advance the throttle without getting squealing. That suggested the squeal was related to heightened alternator load associated with bringing the batteries up to bulk charge voltage.
BTW, there were lot of Nonsuch boats in Three Mile Harbor watching the fireworks last night.