I used the "Adjust" setting, and the needle wouldn't go up from 0. I played around with it for hours.
Tachometer powers on, but does not show RPM
- Thread starter tylcole
- Start date
Yes sir, double and triple checked that they are all connected correctly. It matches the diagram in (1) above. Also, the tachometer turns on, travels through the whole range when it's "booting up", and the engine hours read 0.0 on the LCD display. It just won't take whatever signal is coming from the alternator. The only variable left to isolate is whether the AC tap tach signal (the signal going to the tach) is malfunctioning, but I don't have a comparison to what it should be and I couldn't find online what it should be for this engine/alternator.
I may just have to see if I can find someone starting up their boat and see what their AC tap reads.
I found a video online, you might look on YouTube. I suggest setting pulse to 12 and then go from there.
Also make sure your ground is still grounded while the engine is running. It probably is but I would check it.
It's wired into the same ground as the other gauges. That should be adequate, right? And pardon my ignorance, but how do I confirm that it is grounded?
I tried setting the pulse to 12, and that didn't change it. I also did the calculation that they suggest, which is
(Diameter of crankshaft pulley/Diameter of alternator pulley) * (Number of alternator poles/2)
Which was:
3.25/2.5 * (12/2) = 7.8
And that didn't work either.
The only number I'm not too sure about is that the alternator poles, I just assumed 12 because that's what a lot seem to have. Googling around I couldn't find an easy way to determine it.
Earlier Maine Sail posted you should have 1/2 of the regulated voltage at the AC Tap. Have you rechecked that? (I didn't see where you did).
Most of the settings you have been trying are to set the correct RPM. I would think if the tach was getting a signal it would show something even if it was wrong.
I checked your link you posted of what you bought and see two downloads. One is the tech data sheet and the other is the manual.
On the tech data sheet (it says with and without hour meter) it doesn't have a wiring diagram but it does have pin assignment.
That shows Pin 4 for the signal input.
On the manual download, the one @jssailem posted, it shows the AC Tap connected to Pin 8.
Might be time to call the number on page 1 of the manual and double check the pin assignments.
Most of the settings you have been trying are to set the correct RPM. I would think if the tach was getting a signal it would show something even if it was wrong.
I checked your link you posted of what you bought and see two downloads. One is the tech data sheet and the other is the manual.
On the tech data sheet (it says with and without hour meter) it doesn't have a wiring diagram but it does have pin assignment.
That shows Pin 4 for the signal input.
On the manual download, the one @jssailem posted, it shows the AC Tap connected to Pin 8.
Might be time to call the number on page 1 of the manual and double check the pin assignments.
With a meter or a test light.
It wouldn't be the first time an intermittent connection had some fun with a boat owner.
Maybe the alternator is where the problem lies.
Pardon my ignorance/inexperience, but what does regulated voltage mean in this case? The alternator puts out around 14V, and the voltage I get from the AC tap with the multimeter on AC mode is a steady 4V regardless of throttle.
The other pin assignment is for when the sender is coming off a generator and has both (+) and (-) sending lines, I used the set up they indicate for alternator/AC tap sending line output for diesels. That has the sending line going into pin 8.
Did you ever find the issue? I'm pretty sure that the alternator signal will be a pulsing DC voltage, which I presume the tach counts to provide the reading. If so the signal will vary depending on the type of meter that you are using because it is a DC voltage with an AC component.
Was reading your post as I too have a problem with my tach. It just showed up a few weeks ago. Still searching for solutions to replace it on my 1981 O'Day 34. The hour meter has not been working for some time so as long as I'm working on it may as well just replace it.
Was reading your post as I too have a problem with my tach. It just showed up a few weeks ago. Still searching for solutions to replace it on my 1981 O'Day 34. The hour meter has not been working for some time so as long as I'm working on it may as well just replace it.
The first thing that I noticed on the photo of your alternator is that you have the original alternator bracket with the support on the front gear cover. That system has been known to cause breakage of the aluminum front gear case and these things are now made from "Unobtainium". More than one M25 series engine has gone to the scrap heap because of that bracket.
Westerbeke make a retrofit bracket that solves the problem. It is not cheap but much cheaper than a re-power.
The engine in the photo is M2-12, not M25 though?
Does the same alternator bracket problem apply?
I can't find any specific information.
The bracket looks the same as the one "recalled" by Westerbeke but the Catalina Direct link you posted doesn't list M2-12 as one of the engines that this kit would apply to.
Thanks!
BTW, if anybody is still wondering about the tach issue, I purchased this boat from Tylcole back in May and the problem is still ongoing.
I ordered a new alternator, will rewire and report back, if anybody is interested.
PS sorry for resurrecting an old thread.
I've installed the VDO meter on my boat using 12 as the pulse configuration and it works perfect. I confirmed the RPM with a digital device and it is dead nuts on.
I measured the alternator output voltage using AC voltage and it was around 7 vac. Some volt meters read pulsating DC differently so you may want to check the output with a different meter to verify the reading.
I measured the alternator output voltage using AC voltage and it was around 7 vac. Some volt meters read pulsating DC differently so you may want to check the output with a different meter to verify the reading.
Did you ever resolve this? How?The engine in the photo is M2-12, not M25 though?
Does the same alternator bracket problem apply?
I can't find any specific information.
The bracket looks the same as the one "recalled" by Westerbeke but the Catalina Direct link you posted doesn't list M2-12 as one of the engines that this kit would apply to.
Thanks!
BTW, if anybody is still wondering about the tach issue, I purchased this boat from Tylcole back in May and the problem is still ongoing.
I ordered a new alternator, will rewire and report back, if anybody is interested.
PS sorry for resurrecting an old thread.
I'm not sorry for resurrecting this old thread.
I presume you’re asking because your tach stopped reading RPM’s? If the one for your Beneteau is a Yanmar it probably doesn’t have the same cause as the OP’s Universal. The Yanmar YM tach is driven by a signal wire off the side of the alternator. It’s probably a yellow wire going into an orange wire. It should give a square wave with voltage 0-15V and frequency dependent on RPMs. Check the connections for those wires along the way and maybe it’ll be an easy fix of just cleaning up a bad wire connector.
My tach works fine. The LCD display needs replaced but that's a completely different matter.
I just wanted to know if they figured it out.
if your tack is a "hall effect" or "magnetic sensor" type, it will not use the AC tap on the alternator. I believe it will need a sensor on flywheelOh sorry, this one:
Heavy Duty Tachometers, Hall Effect and Magnetic Sensors | PARTDEAL.com
Buy tachometers for heavy duty applications for less at PARTDEAL.com. Wholesale prices.www.partdeal.com