BF40A Tach Hookup

"I recently bought a used Hond

"I recently bought a used Honda BF40A, and I am trying to hookup a new Honda (Faria) Tach to the supplied used harness. The Tach instructions say to use Honda jumper wire 32197-ZH8-003 on "older tiller models". I found a picture of that "tiller model" jumper on the Honda website, and it looks like that jumper is installed on my harness. But when I connect that wire to the tach, I don't get any tach indication when I start the motor. See attached photo. Tach instructions say that BF40/50 require 06383-ZV5-316 Tach Kit, but I can't find any info on that part on the web, or where to get it. Do I need the "tach kit" if I have the "tiller jumper"? Also, there is an unused 3-pin pigtail at the motor end of the harness (see add'l photo) - what does that go to? BF40A tach hookup to harness"">BF40A harness engine connection

"First...it appears that your

"First...it appears that your motor is not a tiller model so you should not need the adapter. All the leads that you should need are going to the key switch harness through the large round plug in the right of the right picture.

The connector that you are holding in the picture to the right is used for fuel injected engines. It is not used with your motor, so do not worry about it.

The three leads that you will need for the tach can be picked up from the wiring harness assoiated with your key switch assy. You need the grey (tach signal lead), black (ground lead), and black/yellow (switched power lead).

Next...dwpending on the year of your motor, you need to set the tach on the back. Your instruction sheet should tell you which setting to use. If it is 2006 and later...setting 1
If it is 2005 and before...setting 2.


If it is 2005 and before and it acts very irratically, you will need the resistor kit (06383-ZV5-315).

I have found that sometimes even the resistor kit does not work with a faria gauge unless it has a built in hour meter. Do not ask my why and faria can not explain it to me either."

"I put the grey wire below on

"I put the grey wire below on an oscilloscope, and it toggles between 0 and 12V. Connected it to the tach sense signal, and it does give tach output, but it is erratic. When the motor is idling, it indicates about 2000 RPM, and when I increase RPMs, the tach increases to about 3000, then jumps and decreases, then increases again.

I think I may need that resistor network you are talking about (06383-ZV5-316). Any idea where I can get it. Or better yet, do you have a schematic for the resistor network? Is it just a simple power divider?Grey "tach" wire coming out of Honda control box

"Yep! You need the resistor.

"Yep! You need the resistor. Since you are equiped with oscilloscope and are talking about power divider, you know something about electronics.

I do not think it is that complex. They call is a resistor assembly but I am not sure if it is just a resistor or not. It is in a sealed unit. It just runs from the signal lead to ground.

You should be able to order it from iboats. The part number you are using is not correct...it is 06383-ZV5-315. It runs about $17.60. Just a fair warning, as I said before, if your tach does not have an hourmeter it may not completely fix the problem.

If you can not find it on line or from a local dealer...e mail me. We have two in stock."

"Ah, so it looks like the Fari

"Ah, so it looks like the Faria Installation instructions has the wrong part number. I found the part number that you indicated easily on-line. Just tried calling Faria to inquire about he proper voltage level to the tach, which would indicate how to make up the resistive divider, but they are closed Fridays. I will probably call Faria next week, or just bite the bullet and order the part next week.
Thanks!"

"Bought the 06383-ZV5-315 resi

"Bought the 06383-ZV5-315 resistor network from Mike above, and tach works great now. Before I installed it, I buzzed out the part on my ohmmeter. Apparently, this part is just a 1K Ohm resistor to ground (potted in a nice 1" cube case)! The "resistor network" has two leads, one connects to the tach signal and the other to ground. Both ends of the part have both male and female ends to insert in-line. So if someone doesn't want to spend the 20 bucks on this part, I am sure a 1K Ohm resistor between the tach signal and ground will work. It seems like it would be easier to just put the resistor on the back of the tach."

Thought I would add some confirmation to the last post, years later. I asked Faria and got this back from one of their employees:
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The 06383-zv5-315 is the correct number for the tach jumper. Its basically a 1 kOhm 1 Watt, 1 or 5% resistor that goes between signal and ground.

I've ordered some resistors from eBay and will be trying them out shortly.[/FONT]