1983 Yamaha 30EN Outboards Service Manual, Page 74Get this manual
Tightening order and tightening torque: Tightening torque: 1st step 15 Nm (1.5 m'kg, 11 ft'lb) 2nd step 27 Nm (2.7 m'kg, 19 ftlb)
Exhaust covers Make sure the contact surfaces of the cylinder body, exhaust inner cover and outer cover with the gaskets are free of dustI nsta II the gaskets and exhaust covers in the order shown and tighten the bolts
Thermostat and thermostat cover Make sure the contact areas of the cylinder head with the gasket is free of dustAlso check to see that the contact area of the thermostat cover with the gasket is also cleanI nstall the gasket and thermostat cover in the order shown and tighten the boltsTightening torque: Nm (0.8 m' kg, 5.8 ftlb) NOTE: Avoid applying the sealing compound to the gasket