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Bf40a 2007 tach problem

S

shero144

Member
I converted my 2007 elec start, power trim, tiller BF40A to remote control/remote steering. I bought tach/trim 06300-ZW5-000KT and connected to Remote Ctl 24800-ZW4-H13. All color coded wires between gauges and motor were consistent.
The trim meter did not work and Faria replaced it. (Have not had a chance to test replacement.)
The tach is erratic. Spoke with Faria and they had me try all pointer settings which changed results but still erratic. Faria also said I needed 32197-ZH8-003 Sub-harness which hooks up between charge coil and tach sending wire. I now have the adapter. Neither Faria, Honda, or any local dealers are able to tell me how this adapter should be installed. The local dealer spoke with their Honda hot-line to no avail.
Voltages and grounds at the meter seem to be OK. I am being told that there is no other testing that I can perform on the harness.
I have the Honda service manual but cannot figure out how to do this install.
Any help would be much appreciated.
 
A 2007 has the long tiller and has the standard 14 pin connector. I do not see a need for the sub harness. The sub harness is used on 8HP - 50HP, generally older version tiller 40/50 HP without electric start that do not have the proper leads from the regulator/rectifier. So it is used as a direct "tap" off of the exciter and extends a lead to the tach.

Your model (if it is 2007) should have all the correct leads.

On 2006 and newer, the Faria tach should be set to 1. The older units were set to 2.

One thing I have found is that a fix for older engines sometimes is successful in correcting irratic tach. It is really for pre 2006 40/50 but I have found it to work on engines slightly newer. I will go on record to say that in my conversations with the Honda Tech line, District Service Reps, and Faria, no one can explain why it works. As long as you have the Faria tach with hour meter (which is the one you have base on the part number)....if you add a resistor (06383-ZV5-315) to the circuit, the problem goes away.

I have not measured what the value is (someone has said it is about 100 ohms). It is connected between the sender lead (grey lead) and ground.

I have shared this on the forum before and there has been success.

Let me know how it comes out.

Mike
 
Mike,
I tested the TACH with the RESISTOR set installed. Currently boat is in the driveway so I can't yet do more thorough test. [I believe the motor is idling under 1000 based upon experience].
Needle is now steady but readings are questionable. Selector switch set to 1 shows 1600 at idle and smooth rev to about 3000. Afraid to rev higher out of the water. Sel Switch set to 2 shows 1100 idle. 3 shows 900-1000 idle. 4 shows 750-800 idle. As I changed to higher switch settings the needle seems more reluctant to move higher during revs.
There is an unused screw terminal on tach marked SYNC PORT. There is also a small hole in back that is designated ADJUSTMENT POT on Faria instruction sheet. Do either of these come into play?
I also tested the new TRIM meter that Faria sent as a replacement. The needle is pointing straight down. When I turn on the key the needle moves a tiny bit down and stats there. I tried disconnecting the signal lead but the needle does not move.
Thanks,
Bill
 
You should not have to adjust the pot in the small hole.

For the 2007, the setting should be 1.
For 2005 or so, the setting should be 2.
It is very odd that it might work better set at 3.

Just double check to be sure the resistor is installed so that it is essentially shunting the sender (grey lead) to ground (black lead)

Regarding the trim meter.....make sure your sender is connected and is moving. It is the lever on the transom mounting. You have to raise your motor to get to it.

Also, make sure you are connecting your yellow/blue lead to the sender terminal. Double check your connections to the gauge to be sure the right leads are connected to the right terminals. It is easy to switch them around.

Just for kicks...what is your serial number? I want to be sure your engine is actually at 2007.

Mike
 
Last edited:
1. Resistor is installed Bl to Bl and Gr to Gr between the rmt ctl pigtail and the instrument wiring harness.
2. Trim Angle Sensor is functioning. Ohms change appropriately as angle changes(per shop manual).
3. All leads look OK. Continuity between harness engine plug and eye terminal at meter end is good for both sender leads.
4. Motor was purchased by previous owner from Sabrevois Marina, Quebec. It is Canadian.
Frame: BAYS-6400122
Engine: BAYE-3000587
5. I have compared the Honda Shop Manual motor upgrades for 'BF40A4 and later' and this motor has the upgrades. It has a digital ICM.
6. I have compared the wiring diagram in the manual to my engine and found some differences.

Manual: Lg/Bl lead runs from ICM to Trim Angle Sensor.
My motor: Lg/Bl lead comes out of the ICM and is capped on the ICM bracket. The Lg/Bl lead from the Trim Angle Sensor goes directly to the wiring harness plug and out thru the rmt ctl pigtail where is is not used.

Manual: Gr lead runs from ICM out to Tacho.
My motor: No Gr lead from ICM. There are 3 Gr leads from rectifier. One of these leads goes to the harness plug and out to the Tach.
Rectifier leads include Gr Gr W W/Bl GR Bl.

7. What is the SYNC PORT terminal on the tach for?

Thanks,
Bill
 
Easy one first....the sync port is used with dual engine applications to make the two engines run at the same rpm.

Your serial number is no where near anything that I have a reference for....so I am not sure what you have.

As for the trim... Is it possible that someone modified it to use a non Honda trim gauge? In the early years, as you can probably see from the wiring diagrams, the 40 HP had a trim module that the trim sender went to and then the trim module sent the signal to the gauge.

Then in (I think) 2003, to operate the trim gauge, there was a special converter that had to be used to operate the standard Honda trim gauge. They made a special trim gauge that year to work without it... What a pain!

Based on what you said about no Gr at the ICM and three Gr coming from the rectifier, it could be an A4 version

The trim gauge runs off of a varying reference voltage. I think it is 5v. Measure the voltage on the Lg/Bl lead coming from the ICM. With key switch on, I think you will find 5 volts. If so, if you can run the Lg/Bl from the sender to the Lg/Bl on the ICM, I think you gauge will start working. I assume that you have a Y/Bu going to the gauge....

The tach is still puzzling, although, if it follows the rules for the A4 version, I would set the tach to 2.

That is my best guess for now. Let me know about the trim gauge.

Mike
 
1. Yes, 5 volts from the Lg/Bl at the ICM.
2. I connected the ICM Lg/Bl to the Lg/Bl lead to the TRIM ANGLE SENSOR and the TRIM METER NOW WORKS!!!!!!!!!!!
3. THANK YOU
4. More engine info:
The selling dealer told me that it was a BF40AK0 model, 2007.
The cover has the 2006 EPA label.
Model BF40AK0 translates into Engine name BF40A4.
5. I compared wiring diagrams and found that the BAYS 3400530 - 3402486 matches my setup. This is section 19-11 of the shop manual.
It shows the 3rd gray lead from the rectifier and also the ICM trim meter lead going to the Trim angle sensor(the way I just changed it on my motor). There is also a white lead to the Power tilt switch that further identifies that this diagram is appropriate for my motor.
6. TACHO: Would the rectifier signal behave differently from the ICM signal?
Is it possible that this is the wrong tach for this motor?
How can I tell what the number of poles is on this engine?
7. I will test again with selector set to 2. Is there an easy way to check RPMs without getting into expensive equipment?

Thanks again,
Bill

 
Yes the signal differs between the rect and the ICM.

The signal from the rectifier is a 6 pole setting and should be set to 2
The signal from the ICM is 2 pole and should be set to 1.

The years and the model numbers are very confusing on your motor. In the USA, a BF40A4 is a 2004. The BF40AKO began in 2007. I wonder if someone changed the powerhead at one time?

Very confusing!!!

Mike
 
It is fun to brainstorm with someone like you, who is deep into the repair manual.

If you look closely, after the BF40A4 comes A5 and A6 before getting to AK0. A4= 2004 A5=2005 A6=2006

I do not understand how you think the A4 translates to AK0. Up to 2006, most of the time, Honda had model years. In 2007, that changed and they do not associate years with their models. Why? I do not know.

Also, note the serial number ranges....yours is no where in sight. That is why I am confused with where your engine fits.
Are you sure your serial number is BAYS-6400122 or could the 6 be a 3? Easy to missread the plate. Then most of what you are finding would make sense.

Mike
 
Mike,

1. Tested tach(on #2 setting) and it shows a steady 1100 with a smooth rise to 3000. Still in driveway so I can't test more yet. This could be an accurate reading? What is normal idle for this motor? I checked carbs to be sure linkage was all in idle position. When I pressed down on the linkage to slow the engine to 900 reading it kept running but was rough.
2. Took photos of serial number plate but cannot figure out how to upload them to this post. The six is a three. BAYS-3400122 BF40A....... Scratches on plate made it look like six. That is my story and I am sticking with it!
3. Called Honda, Canada and they were only mildly arrogant. They looked up the serial number and confirmed that the motor was originally sold by Sabrevois Marina, Quebec, on AUGUST 18, 2004 and that it is a 2004 motor. No explanation as to how the motor cover has a label indicating "2006 EPA Standard".
4. Only inconsistency with shop manual is with 2 different wiring diagrams where [BAYS 3400001-3400529] shows W/Bl to Trim Switch while [BAYS 3400530-3402486] shows W to trim switch. My motor has W to trim switch. I can't find any other differences between these 2 diagrams to compare to my motor. (Wire Diag in my owner's manual also shows W/Bl!!!)
5. The hondamarineparts URL I sent in a prior reply makes a distinction between MODEL NAME and ENGINE NAME. That is where I see ENGINE NAME BF40A4 repeated 11 times starting with MODEL NAME BF40A and ending with MODEL NAME BF40AK0. This is now a moot point.
6. I apologize for taking more of your time than I should have because of erroneous assumptions.
7. I believe that the tach is working correctly but will have to wait for a launch date to experiment further. Maybe I can find someone to measure my RPMs at some point.

Thanks,
Bill
 
I would set the idle to about 1000 rpm while on the hose. It will come down a little once in the water. The book (since you know it back and forth by now) says it should be 950 plus/minus 50.

The 2006 EPA sticker has been on the Hondas since the 2006 standard was established by EPA or whomever. Since Honda was the first to meet the standards on almost all their motors, even at that time, they took advantage of the additional Marketing. I can see where it would be misleading.

Don't sweat the time...think how much we learned.

With a little idle adjustment, all should be well with the world.

Mike
 
I finally got the 13' Whaler into the lake. Took my wife and daughter... approx 410# load(3 of us).... TACH and TRIM worked great.

Only question is why tach goes over 6000 RPM?

backed off at about 6300 for fear of bad things happenning. Other than that I cruised at 5000 RPM for a few hours.
The prop is 11.1X13HQ

I kept the trim level at all times.
I am using 91 octane gas(non ethanol)

Thanks,
Bill
 
More questions....

Did it hit the rev limiter? It normally should about 6300 - 6400 rpm. It will feel like someone is trying to turn the engine on and off.

What boat was this motor on before you converted it?

If it was on a different boat, then it is very possible the the prop is not big enough diameter.

Did you finally set the tach on 1 or 2?

Mike
 
I reduced throttle before the rev limiter could kick in.
Next time out I will let it wind up to see if I get the reaction that you describe.
The motor was originally on a stitch and glue homebuilt 15' duck boat which I believe is a bit heavier than the whaler. There was no tach so I don't know what RPMs it turned.
I bought a second prop for the motor and the size seemed to be a standard size prop for the motor.
The tach is on 2.
Thanks,
Bill
 
Just wanted to bump this thread again. Have a 1999 bf40 and am looking for a tach. Called Fariah and they said any of their 7000 rpm tachs (with or without hour meeter) will work for this, but the responses above seem to indicate otherwise.

Can anyone chime in before I purchase a tach?

Thx!
 
I THINK you need a Honda brand tach for the 35-50 A models. Just going from memory, but I don't remember the reason. Point being, suggest you keep looking into it further. Decent source for Honda tachs would be ebay if you decide to go that way.
 
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