occassionally starter doesn't spin

[bforsythe1]

I have a 30hp jet with 2008 f40 78 hours total-went upside down on Klamath river-I totally rebuilt it-got the sand out, but sometimes the starter doesn't spin. I replaced solenoid switch and did complete checkout or starter- there are no switches in there-could it be the starter thats not working on occasion. I can hear a little noise from that area when it doesn't work but when I turn key. Then before I can test it, at home and after I have manually started it it will work fine. Can starters work intermittently?

[99yam40]

Check the start relay