Early this morning as I was installing new alternator belt...

[1911tex]

Neighbor boat had an old time boat mechanic working on his engine. This fella saw me sweating in the high temps/humidity and advised to drink lots of water. He asked how I was tensioning the new belt. I demonstrated the 1/2" deflection on longest length of belt. Started engine and the belt was flopping like it was loose. He said..."let me show you an old timers way of doing the adjustment"...I said "have at it". He showed me that a 90 degree deflection on the the longest length of belt was easier and more effective than a gauge or using the 1/2" method. I never knew of this method, so I started the M25 5421 and the belt ran smooth and vibration free...could not believe it! He also reminded me to recheck tension on the new belt for a few months as it will normally stretch a little. I have his card and will call him when and if I need anything fixed that I cannot fix myself...which means I will call him.

I went home to shower and check YouTube on this 90 degree method of belt adjustment and ran across this video:

 

[Nick J]

That's a great tip. Much more solid than a deflation measurement. Now if I only had a tensioner like that (I have to pivot the alternator to achieve tension)

 

[nquigley]

Excellent - now I just gotta remember it when I next tighten the belt ... wait ... I'm in the middle of replacing some coolant system gaskets, so my belt is off now - perfect timing for learning this trick. Thanks!