TOPIC: Tack

I have what appears to be a mercruser v8 tack will it work on my
1971 4 cyl 80 hp motor with electronic ignition

Charles

Hi Charles,
For most V8 Mercruiser tachometers, it would not work on the outboard's Thunderbolt Ignition, but there were some Mercruiser V8s produced which did use the same switchbox (ignition module) I believe, and would work (if the rpm range is high enough for the outboard). Also, many newer tachometers can be "set" on the back for more than one application. If so, it may can "read" from the outboard charging system. If you could post pictures of the front and back, I may can identify the tachometer if I can see details well, or if you should happen to have the factory part number. If your pictures are too large to post here, you may send them to me at This email address is being protected from spambots. You need JavaScript enabled to view it.

Regards,
Joe
www.fergusonpoolemarine.com
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I thought that this one ran to the trigger side of the coil can you use a automotive tack on this system the motor has the next model ing. in it this is the tack that I have

Hi Charles,
Although I cannot really see the labels for the terminals, you appear to have an alternator driven outboard tachometer. If your battery charging system is functioning, you can connect this tachometer successfully. To successfully connect the tachometer via the use of a tachometer harness plugged into the MerControl, the brown tachometer sender wire likely connected to the four terminal side of the switchbox will need to be removed and moved to be connected to either one of the yellow with red stripe wires connected to the rectifier.

Regards,
Joe
www.fergusonpoolemarine.com
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the tack came out of a instrument panel that had gauges for a inboard motor could the used it for that to read the pulse of a v8 aren't the alt tacks for 8 pulses also
Charles

Hi Charles,
The outboard stator has six pulses per flywheel revolution, the Mercruizer V8 would only yield a signal from the ignition system (four pulses). I am still pretty sure of my opinion, as the tachometers for Mercruisers typically read to 5000 rpms, not 6000 rpms as was the norm for outboards.

Regards,
Joe
www.fergusonpoolemarine.com
This email address is being protected from spambots. You need JavaScript enabled to view it.

I will try it on my 65 and see if it works can compare to the tack that I am running on it thanks for the info
Charles