90 hp 4 stroke questions

[spareparts]

I rarely see anyone adjust the valves, it s a PITA to do. I've checked them for people from time to time and rarely find them out of spec, If you decide to check them, make sure you do a strong decarb treatment before you check them. My friends that run the harbor taxi checked theirs every 1000 hours,they kept the same timing belt on till Yamaha offered to pay to have the belts changed at 5000 h ours, they wanted the old belts back. Those engines were sold at 8700 hours