4 stroke question-timing belts

[dcarter9]

Are the 4 strokes considered "interference" motors? Has anyone heard of a timing belt breaking and causing problems. The motor in question is a 2001
F115.
Also I noticed that the valves are to be adjusted/inspected at 400 hours. I called 3 local Yamaha shops in my area to inquire about getting them adjusted and none of them have ever done it? In the catalog it looks as if they need to be shimmed.
Any comments on the above questions?

[boats.net]

Yes they are interference motors, as long as you replace timing belt every 1000 hours you shouldn't have any problems. The valve clearance does need to be checked at 400 hours and they use "shim over bucket" lifters and if adjustment is needed then will have to exhange shim.

[dcarter9]

Thank you for the quick reply!