[bigba1]

16.5 hp briggs, new battery and starter, starter spins but does not engage. 2 of the copper wire coils under the flywheel gets hot and the wires going to it

[DG]

Make sure you have the battery right ,sounds like you have the cables on the wrong side,

[ballengerb1]

Try DG's suggestion. If that is not your issue then you might remove the starter and take a look at the starter bendix. When the starter spins the shaft spins and a nylon gear should slide down the shaft as it spins. This gears enagages with the flywheel but if the gear or the shaft aren't working the engine won't turn over

[bigba1]

WOW that's embarrising I should know better than that, I did, new battery was reversed of the old one, just put the fly wheel on mower fires up. Thanks DG

[ballengerb1]

DG spotted something that never dawned on me. Batteries can have posts reversed but appear the same. Always us the same product # and watch for the letter R in the product #. Maybe stop by and give DG a positive check mark, I did.