73 merc 850 thunderbolt. Just hooked the stock tach up and its only reading 3500 rpms. Just got engine and have been fixing slowly. Put in a new trigger from cdi, and I'm doing the timing belt tomorrow. Can I use a dmm with frequency setting to check pulse from engine, (brown wire) to see if it's the tach reading low or the engine not spinning fast enough? What would that be like 60hz at about 3500rpm? Also, does anybody know if I need a flywheel puller to change timing belt? Thanks all.
