VP2020D Alternator Belt Wear

[Porthandbuoy]

An idler pulley might be the simplest way of solving the problem. ( I'd look at doing that first) Can you talk to the Yanmar people to see if they have a solution?

When you talk of changing to multi "V" pulleys that can be a big job. Boring the pulley blanks, cutting the keyways? (?) (Been there, done that)
You would need a double "V" pulley on the crankshaft, water pump(?) and the alternator. You are no doubt looking at $500+++ to get someone to do it for you and fit it.

V belt tensioner for sale | eBay

Have look here: https://electromaax.com/helper/printad/adId/14653561

 

[MikeBz]

I had the same problem of belt wear and lots of dust on our MD2020D when I fitted a Sterling A2B. New Volvo belt - no different. Then I (a) linished the pulleys so they were smooth and rust free and (b) fitted a Gates belt (can’t say which one right now) - never had a problem since.

Edit: QXPZ800 Gates Quadpower Belt

 

[coopec]

Have look here: https://electromaax.com/helper/printad/adId/14653561

Great!

So Yanmar has a serpentine kit at $US435 (Fit it yourself)

But I worry: you have to get a new alternator? If that was the case it would cost another $500+ (maybe I am mis-reading their blurb?)

Description
Now Includes Free Electromaax Tension Arm**
This very popular Yanmar marine 4JH-E 44 HP, Entered into the market in 1983 and finished in 1989. This raw water cooled engine now has an Electromaax Serpentine Pulley Upgrade Kit that is very easy to install. Allow approx. 1 hour the first time you do this simple installation. When purchasing any Electromaax marine alternator the pulley can be installed for you at the factory. The new 10 groove serpentine (micro ‘V’) crank pulley simply slips over your current crankshaft pulley and is secured with the bolts supplied. The new serpentine water pump pulley simply replaces your original. When replacing the original Hitachi alternator with your new Electromaax Marine alternator the installation has been eased by utilizing the factory Yanmar connections making this upgrade “plug and play”.
Helpful install hints 1. When loosening the 4 water pump bolts leave the existing belt in place THEN undo the bolts. This way you can use the belt to stop the W/P pulley spinning. 2. Check the threads in the existing crankshaft pulley have not rusted. We find in most cases a little grease on our bolts clean the threads out if you carefully put them in half a turn and back. Alternatively you can use the correct thread chase (typically metric). This popular Yanmar Marine engine, and all other engines operate much smoother, quieter and virtually eliminate belt dust with a serpentine upgrade kit. Additional benefit of an Electromaax kit is the ability to drive auxiliary devices ie: Seafrost refrigeration, engine driven water maker, second alternator, compressor… with the addition of a second crankshaft pulley. Contact us for further details You can now safely operate the Electromaax SM-12-80, 100, 120 or 140 amp marine alternators that produce up to 70% of their output at fast idle. Our SM-12-160 amp unit will also work to"

https://electromaax.com/helper/printad/adId/14653561