a friends boat in La Paz. He installed a new Yanmar in his 38 foot boat last year and because of circumstances beyond his control didn't use the boat away from the dock for almost a year. On the way from Mazatlan to La Paz he started to burn the alternator belt. He thought it was a bad water pump and changed it underway but the same thing started to happen again. He had to run at a reduced RPM and was able to make it to Marina Palmira. It felt like the belt was tight enough and in fact, when we used a pry bar on the pump to pull on the pressure we couldn't get any more stretch. It still did the same thing. Finely I got my head down into such a position that I could see the back of the pump and found out that the pump was actually bottomed out on the adjustment slide. It only felt like the belt was tight because we were pushing against the stop. The belt must have been right at the point where it would slip but was close to the maximum 3/4 inch deflection that they require. You couldn't see that the pump was bottomed out from the front. The belt was provided by Yanmar along with the new pump so we figured it was all the right stuff but found out the hard way it wasn't. I would double check the belt tension.