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RPM Gauge not working

Posted: Sun Apr 25, 2021 2:57 pm
by starfish
Hello, not sure if this should be on the Engine Forum or Electrical.

After some engine work I noticed that my RPM gauge is not working. Can anyone tell me where the gauge is connected to the engine? Or even better, show me a picture of where it connects? Is it a wire?

2005 Hull: 333

Thanks for all your help.

Ed

Re: RPM Gauge not working

Posted: Mon Apr 26, 2021 9:23 pm
by leigh weiss
the engine RPM gets it's signal from the alternator tap. If the alternator works and you show about 13 + volts with the engine running, then the most likely culprit is the rotary switch on the back of the tachometer (multi position rotary switch) make note of the number position and turn it several times back and forth, to clean the internal contacts. Hope this helps you. Lets us know how it goes.

Re: RPM Gauge not working

Posted: Sun May 02, 2021 2:40 am
by D&M
Tachos on these boats are notoriously unreliable. You should get an ac voltage on the S term wire of the tach with engine running (varies with engine speed but not by much). If you do and it does not respond with a reading on the guage then it is probably hosed. You can buy a cheap replacement on ebay like I did (works fine). Or go for the original looking device on Catalinadirect. Note which ever you choose will not show the original engine hours. Just have a calculation in your logbook which pertains to the old numbers. (The engine hour meter should be functioning correctly) even if the tacho is not.

Re: RPM Gauge not working

Posted: Sun May 02, 2021 8:09 am
by wolfe10
leigh weiss wrote: Mon Apr 26, 2021 9:23 pm the engine RPM gets it's signal from the alternator tap. If the alternator works and you show about 13 + volts with the engine running, then the most likely culprit is the rotary switch on the back of the tachometer (multi position rotary switch) make note of the number position and turn it several times back and forth, to clean the internal contacts. Hope this helps you. Lets us know how it goes.
Absolutely, try this first-- worked for me.