Headbolt Pattern & Torque - 1963 Seahorse 40

[cknadroj]

Hi:<br /><br />I've ordered a manual, but while I wait for snailmail does anyone know the bolt numbering, tightening pattern, and torque spec for the headbolts on a 1963 Seahorse 40 HP?<br /><br />Also should I run 50:1 premix or some other ratio?<br /><br />Thanks for helping the new feller.

 

[WillyBWright]

Re: Headbolt Pattern & Torque - 1963 Seahorse 40

Welcome to iboats.<br /><br />This isn't according to the book, but I think it's a better method...<br /><br />Start with the center bolts and work outward in sort of a spiral. Torque to 1/2 value the first time around, 3/4 torque the second time around, and full torque the third round. Then I run around and recheck all of them in a circle.<br /><br />Numbering from left to right and top to bottom there should be 10 head bolts on a twin. Torquing order 5 6 8 7 3 4 10 9 1 2<br /><br />50:1 would work well in that motor using any good 2-stroke outboard oil.

 

[Paul Moir]

Re: Headbolt Pattern & Torque - 1963 Seahorse 40

WillyBWright, I don't know which book you've got but that matches mine exactly. <br /><br />The torque should be 168-192 inch/lbs (14-16 ft/lbs). Do this with an inch/lb reading torque wrench since ft/lb reading wrenches are woefully inaccurate at this range. Also, repeat the tightening sequence after the engine has warmed up and cooled off.<br /><br />24:1 is what was originally recommended for your outboard. I wouldn't have much reservation about going leaner. Check out the Oil Mix FAQ in the FAQ forum for details.<br /><br />And welcome to Iboats!