Re: 75 merc 8500 wont start
Yup, I bet someone unbolted the flywheel from the flywheel 'hub' and lost the relationship between the two.<br /><br />Easiest way to verify it's off is to bring #1 cylinder to Top Dead Center, or as close as you can to it.<br /><br />At that point the timing marks on the flywheel (or timing scale if it's on the flywheel on that model) should line up to any TDC marks you have. If the marks/scale on the flywheel are way off, it's a sure indication the flywheel orientation is off.<br /><br />You'll need to unbolt the flywheel from the center hub and reposition accordingly. Since there's only so many positions you can orient the flywheel to, it should be obvious when it lines up properly. Only one orientation on the hub/flywheel interface will properly align.<br /><br />Then realign the belt and off you go!<br /><br />I did have an unusual case once, where the alum cogged drive hub on the flywheel itself was split and would rotate around, making the timing change all the time! Very strange problem, but easy to check with the hub off the crankshaft.<br /><br />P.S. be sure to have no more than 21 deg max timing advance at cranking speed, for a bit of extra security set it at 18-20 deg BTDC.<br /><br />And be sure to use a drop of red Loctite on each flywheel hub bolt. Torque to factory specs for your motor.<br /><br />HTH and Happy Timing........ed
