Faria tachometer on Yanmar

[micky]

How can I know the pulses my alternators produce so I can set the dip switch on the tachometer? I have faria tachometer and Yanmar 315 engines.

[scenarioL113]

I dont know about Yanmars but I know that Cummins use a flywheel tooth counter that is a magnetic switch that screws into the bellhousing. They work very well and work on any flywheel as long as you have a threaded hole in your bellhousing.

Look on the opposite side of the starter to see if there is a threaded hole...

[micky]

I just saw it on my engines. I will cut the signal wire from the alternator and connect the sensor in the bellhousing.

[scenarioL113]

I was looking at your pics of the engines and I do see the sensor. Give it a try. You might have to troubleshoot the dip-switches on the tachometer. You will prob need to know how many teeth are on your flywheel and then search "faria" for a reference guide or sheet that can help you with figuring it out. Look on their website.

*note* their is prob 2 connections on the sensor. "1" of them has to go to ground and the "other" goes to your gauge. It does not matter which goes where...

Good luck

[micky]

Just did this and the needle on the tack goes pointing down to 6 o clock and doesnt move.

[Carl]

https://fariabeede.com/site_manuals/IS0015_H.pdf



Frank- I think its a different gauge and pickup for Flywheel magnetic pickup and Alternator pulse count.

[micky]

Anybody know how many poles does the alternator has? Or in which number the pole setting goes? The tach has 6 positions to choose from.

[Bruce]

Alternator output is the least accurate as belt slip will affect the readings. The tach output comes from an ac tap on the alternator and the tach should have that connection marked already depending on the faria model.

The tach output on the bellhousing picks up the teeth on the flywheel. As each on goes by, that is considered a pulse. The tach unit on the bellhousing has two wires, they both go to the tach. Some Faria gauges have a rough adjustment and then a fine one and to get it right on the money you need a reflection tape tach pickup to be accurate.
It would help to know which model Faria gauge you have also.

I'm at work and will look it up later but 118 comes to mind for the LP bellhousing pickup.

[scenarioL113]

If you look at the PDF and specifically at wiring section and look at 8 "A", I think that is the same type tooth counter option that is like our Cummins. The tach should accept it....maybe....

[micky]

Alternator output is the least accurate as belt slip will affect the readings. The tach output comes from an ac tap on the alternator and the tach should have that connection marked already depending on the faria model.

The tach output on the bellhousing picks up the teeth on the flywheel. As each on goes by, that is considered a pulse. The tach unit on the bellhousing has two wires, they both go to the tach. Some Faria gauges have a rough adjustment and then a fine one and to get it right on the money you need a reflection tape tach pickup to be accurate.
It would help to know which model Faria gauge you have also.

I'm at work and will look it up later but 118 comes to mind for the LP bellhousing pickup.

I thought 1 of the wires was ground and 1 signal.

[Bruce]

It is but ground it at the back of the instrument.
The signal is susceptible to RF noise and electrical noise which is why to be 100% sure of proper connection you use a twisted pair of wires to reduce the chance of noise screwing up your tach signal.
I have seen one side grounded at the engine and work and more times than not it doesn't read accurate because of some noise.

On many repowers I've used a two wire shielded wire for tach signals and ground the shield for extra protection.

So many times there is resistance at different ground points on boats which is why navigation and tach signals have to well grounded for interference.

Now seeing what electrical you have redone on the boat you may not have those issues, but I have seen instances where the radio was keyed up and the tachs went haywire.

[micky]

So just replaced the Faria tachs with the Yanmar tachs and WOT in neutral went up from 3800 to 4300. I confirmed this with the photo tach. So if the readings across the board has the difference of 500 rpms, running WOT should go up from 3100 to 3600. I will seatrial again this week and report back. Hopefully the props just need a little adjustment. I need to reach 4000 rpm.

[scenarioL113]

Can you post some videos of your seatrial. I for one would love to see your Hatteras in action

[micky]

Can you post some videos of your seatrial. I for one would love to see your Hatteras in action

On page 14 of the Hatteras thread I posted 3 videos.

[scenarioL113]

I missed those. Hopefully you can take another seatrial now and see what RPM you are really getting... IMO you would be smoking a lot if you were that heavily overpropped but who knows. Report back on the other thread when you get the tachs squared away