Was doing some carburetor adjustments and noticed the fan belt drifting back towards the block on the crankshaft pulley when I throttled up the engine. How odd.
The pulleys need to be in perfect alignment and have a high center which tends to pull the belt toward the center. Also, the belt itself should not be stretched because it can stretch more on one side than the other and if so, the only cure would be a new belt.
When you install a belt, just tighten it enough so that it doesn't slip, but loose enough to ride on the high centers of the pulleys.
Mark, usually they run to the front of the pulley, and the cure is ti slightly bend the fan arm upwards to bring the shaft into line with the crankshaft. Perhaps you need to do the opposite.
Sometimes the cause is a bent mounting bolt. If you turn that and the fan arm waves back and forth, there is your problem.
Hope this helps.
Allan from down under.
Like Norm said and I never had a problem ever since. What kind of belt are you running? Leather looks nice but never worked for me. Rubber works great.
A straight edge will tell instead of guessing.Bud.
Funny, Imdon't recall seeing this before. I'm running a rubber type belt right now.
I have had to add a washer between the fan bracket and the front cover on both of my '13s to get them to track properly. I agree with Dave, I like the new Gates rubber belts from Mexico.