Logo
FULL SITE MENU

Tachs not working right? 1996 7.4

G

gemiii

New member
I have twin 1996 7.4GL's in my 49 Holiday Mansion. I guess the tachs get signal from the alternators. They used to bounce all over the scale but now 1 of them isnt reading at all. You cant hear the engines run or crank over because they are far from the bridge so I count on the tachs to know if they are running. I had both alternators redone in the last 2 years. Both helm tachs are reading the same on each engine so I am guessing its a ground or alt issue?

Thanks in advance for any help!
George
 
Re: Tachs not working right?

If the rpm tends to over read and seems to float, it is likely a ground issue - mine was.
 
Re: Tachs not working right?

Typically on inboards, the signal for the tach comes from the ignition system... usually from the low side of the ignition coil's primary, i.e., that which connects to the distributor. Check your owner's manual. Usually has a wiring diagram of the engine.
 
Back
Top