Throwing Serpentine Belts

Hello All, recommissioning my 01 310 with 350 Horizon/Vdrives, after 4 years of inactivity. Have motors started, but struggling with keeping the serpentine on both motors! The pulleys did have rust and I have tried to clean them as much as possible while attached to motor. All turning parts are turning freely. Have checked alignment from raw water pump to crank pulley. That was off a little on one motor. Removed pump. Cleaned all mounting holes and that is better, but belt still wants to climb off of the rw pump pulley. Pulleys are perfectly aligned now. The other motor throws it almost instantly. I thought serpentines were a little more able to compensate for slight misalignment. Any thoughts would be appreciated.

 

Thanks for the replies. I did find that and checked it today. The odd thing about this is that I have had the boat for a few years and ran it for 4 years before laying it up and I have never had an issue before. So, obviously looking at the rust on pulleys, etc. But that being said, the alternator on one motor was way out of alignment and I adjusted that. The RW pump was way off on the other one, fixed that. But, it had run that way for a few years. There is some common denominator that I haven't found yet. The belt on both motors is trying to come off the the RW pump. Half of it literally rides off.

 

So, continue to chase this issue. What I have deduced is that while rotating the engine in correct direction, the belt goes from the stationary idler, down to alternator, to circulator pump pulley than down to crankshaft pulley. As it goes from alternator to the circ pump, it starts to climb off of that pulley, and subsequently the crank pulley. It appears my alternator pulley is out significantly from the crank pulley. I have removed it twice to check everything. All seems ok other than alignment. I will try to post pics of the measurement. If there was a way to get the alternator moved rearward, I think the issue would be solved. The crazy thing is that this boat ran this way for a few years. I don't understand what has changed by letting it sit. I am stumped and just stewing on it for a while to come up with a solution or reason. Any help gladly accepted!

 

Fully aware of the rust and taking care of that as I go. Here is the service bulletin. My pulley is a good 1/2" out from the crank pulley.

 

Will do, thanks

 

The idler bearing is fine, have checked it. When I had to put the boat up, there had been some salt water flying around the engine room. Thought I had sprayed everything down with fresh after. Plus, here in the northeast, you would have to be in a perfectly controlled environment to stop rust. Let alone this poor thing has sat out for 4 years. Albeit covered, there is still lot's of moisture in the air and not always able to breath. Will work on the rust issues as I can.

 

Ordered a new pulley for the one alternator that was really bad.
Worked on the other engine all day. The alternator is just so far out of whack with the crank pulley. I did find a roll pin/bushing on the front part of the alternator top mount and adjusted that which brought the alternator back some. But now when I start the motor, it just throws the belt right away. With a straight edge I am now parallel with the crank pulley at the top, but rotate the straight edge down, still on the alt. pulley, and at the bottom of crank pulley I am half inch out. I am almost out of options and ideas. Just decided to walk away for the day.

 

Pretty sure it was directed at me. Working on the trim/shim scenario