If you have an o-scope then it's pretty easy. Should just be a square wave coming from the pickup....while the engine is running. Pretty sure the QMs used a flywheel pickup the same as the HMs and GMs. Otherwise it is possible to use a volt meter on AC to detect the voltage, again with the engine running.
Alternatively, use 2 people, one watching the tach and the other wiggling each connection from the pickup to the gauge. Pretty likely that it is the tach. They are not water or rust proof. Mine needed replaced when I bought the boat 3 years ago. Don't just go with the "recommended" part. Look for one that has an hour meter built in. They make 'em. Josh Muckley S/V Sea Hawk 1989 C&C 37+ Solomons, MD On Jul 6, 2015 2:16 PM, "David via CnC-List" <cnc-list@cnc-list.com> wrote: > ...after working intermittently on a 3QM30. I remember hearing here an > easy (ish) way to check whether it is connection to engine or tach itself. > > Thanks in advance!! > > David F. Risch > (401) 419-4650 (cell) > > _______________________________________________ > > Email address: > CnC-List@cnc-list.com > To change your list preferences, including unsubscribing -- go to the > bottom of page at: > http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com > > >
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