Tach question

[Dave]

All season there has been no problem .Recently the tach started not regstering. At the same time the volt meter now only shows 12 volts instead of the usual 13 plus.If I am correct the tach is regulated by the alternator. Thus I cleaned all the connections coming off the alternator and checked the connections at the back of the instrument panal, Still the same problem. Any suggestions are appreciated.Dave

 

[Hans]

Check V-belt

Usually, the tach is fed AC from one of the three windings in the alternator. Seems like this winding isn't putting out which explains both the tach not registering and your voltage drop. Things to check:a) v-belt: maybe loose (alternator not turning): it should be so tight that you can depress the longest free part by 1/2" with your thumb.b) winding is burnt up: if the belt checks out, take the alternator to a (automotive) alt. rebuild shop for a checkout / repair.c) if you have a fancy external electronic regulator (multi-stage), take it to the shop too for a checkout.d) in any case, take a voltage measurement directly at the alternator output post (your wiring maybe at fault)Good luck!