Eating belts

KD3PC · Jul 10, 2011

V belts...should be adjusted for about .5" per 12-15" of distance, adjust for longer distances. Not sure what the 20 lbs is, if you are using 20lbs deflection, rather than just pulling with your finger or a gauge, you are likely too tight. Never put your finger or hand under or on the belt when engine is running.

You need to make sure that the belt is riding the two sides of the pulley, not in the bottom. And that both sides of the pulley are rather smooth.

Some of the new (cheaper) belts will dust, but should not be extraordinary. Make sure that the belt is not rubbing something it shouldn't and examine the ruined belt to see where and how it is wearing.

Those things should give you at least a year or better of good service.

Don12364 · Jul 10, 2011

Do you have the stock 55 amp Hitachi alternator or has somebody 'upgraded'?
Original alternator is normally painted at same time and same colour paint as engine.

iwillmott · Jul 10, 2011

bustedrudder said:
We motorsailed our "new" 94 40.5 from SC to FL over the 4th July weekend.

Yanmar 4JH2E.

Adjusted the alternator belt beforehand, then daily from there. Replaced after day 2 and still can't get more than a day without excessive dusting.

Alternator is a 129470-77200 (80 amp).
I've put a straight edge across pulleys and the alignment seems perfect.
Checked as close as I can and the groove angle seems consistent across flywheel/pump/alternator.
With belt off, everything free wheels fine.
Adjusting so that i get about 1/2" deflection on longest stretch and about 20 lbs.

I'm at a loss. Only running a refrigerator, no huge load involved.
There has to be something i am missing (as a new dumb owner)

I would like to know what happened..I just bought a 40.5 , same power

Steve Dion · Jul 10, 2011

This issue has been addressed before. What type of belt are you using? Are they OEM or some other mfg.

There have been issues that the belts are not the proper "V". I think that the Gates belts are supposed to be good as well as the Yanmar belts.

sailaway78 · Jul 11, 2011

Think 1/2" is way too much

I think that 1/2' deflection is way too much. Not sure what you mean by the 20 lbs. An 80 amp alternator is approaching the upper limits of a single belt system, so the belt needs to be pretty snug. Also, what kind of belt. If you have a belt that is too wide, or one that is too narrow, will wear pretty fast. The engine and alternator are metric, so you can't just throw any belt on there. I have a 3GM, with a 70 amp Hitachi, and have a pretty constant dusting problem, although don't have to constantly tighten the belt, and it's not severe.

Rick D · Jul 12, 2011

Gates...

....Green Line if I recall. I have a 90 amp Balmar and used to get some dusting from my stock Yanmar. But since changing to the Gates, much less. Some dusting is normal, especially with a new belt, so not to worry too much. Three or four belts in 2300 hours, and all for maintenance reasons only.

Bob Mack · Jul 12, 2011

RE: Eating Belts:

I have a 3JH4E with a 1/2" nom. belt, driving a Amptech 125 Amp alternator with a Balmar ARS-5-H external regulator to prevent overloading. Initially I used a 1/2 Gates standard belt with poor results. Tried one of the Gates belts with a green woven cover, which dusted terribly and lasted only a few days. Last year went to a Gates gogged belt ([FONT=&quot]NAPA L25 9440) [/FONT]and left the adjustment tension at about 1/2". Belt has lasted 1-1/2 years and only minimal dusting.