What is causing this alarm on my Honda O/B?'

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C Buchs
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Re: What is causing this alarm on my Honda O/B?'

Post by C Buchs » Thu Jul 30, 2020 2:10 pm

My Honda 50 had the same problem and it turned out the be a bad tilt sensor. I found some instructions somewhere on how to bypass it with a jumper wire. You could at least try the jumper wire to see if it solves your problem.

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Re: What is causing this alarm on my Honda O/B?'

Post by DaveC426913 » Thu Jul 30, 2020 4:08 pm

C Buchs wrote:
Thu Jul 30, 2020 2:10 pm
My Honda 50 had the same problem and it turned out the be a bad tilt sensor. I found some instructions somewhere on how to bypass it with a jumper wire. You could at least try the jumper wire to see if it solves your problem.

Jeff
Thanks. Will check that out.
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Re: What is causing this alarm on my Honda O/B?'

Post by Jimmyt » Thu Jul 30, 2020 6:51 pm

DaveC426913 wrote:
Thu Jul 30, 2020 4:08 pm
OK. Here's the part where everybody pelts me with socket wrenches for not having mentioned it earlier...

Pretty sure one of my batteries is dead.

I assumed, as long as I only run the good battery, it shouldn't matter.

And now you're gonna ask me if it's the deep-cycle or the starter battery that I've been running off.
You're not close enough for me to pelt you with anything. Besides, I'm working on my own stuff while you are entertaining us with a bit of a mystery. So, it's all good.

I ran on my deep cycle last time out. Shouldn't make a difference, as long as you weren't switched to BOTH on your battery selector.

Can you get us some info on the sensors? Without knowing what you have, it won't be easy to explain how to check it. Page out of the service manual, picture of the sensor, anything to help nail down what type of device it is. If it's a temperature sensor, and not a thermal switch, it's a bit more interesting.
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Re: What is causing this alarm on my Honda O/B?'

Post by opie » Thu Jul 30, 2020 7:06 pm

tilt alarm is my vote. Just remove it. It is unneeded.

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Re: What is causing this alarm on my Honda O/B?'

Post by Jimmyt » Thu Jul 30, 2020 7:27 pm

Does the tilt sensor cause an alarm when the engine is not running and not in gear? He gets an alarm when the key is on, but engine is not running.
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Re: What is causing this alarm on my Honda O/B?'

Post by Jimmyt » Thu Jul 30, 2020 7:30 pm

Found an 03 wiring diagram. Looks like water and oil are switches- not sensors. Try pulling the wires off of each while ignition is on.


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Re: What is causing this alarm on my Honda O/B?'

Post by Be Free » Fri Jul 31, 2020 8:38 am

The BF50A is the first generation carbureted engine. There are very limited diagnostics built in. The alarm and lights are for low oil pressure and high temperature. There is no low voltage alarm. A continuous alarm without looking at the lights on the shifter does not tell you what is wrong. You will need to look at the lights on the shifter as well. The factory install had the shifter rotated down 90 degrees which makes the lights very hard to see.

Both lights off and a continuous alarm is low oil pressure.

Both lights on and a continuous alarm is high temperature.

Oil light off and temperature light on with a continuous alarm is low oil pressure and high temperature.

If you are getting any of these indications and you are SURE that you don't have the indicated problem the sensor is the prime (and cheapest) suspect. Make sure that the wire connected to the suspect sensor is clean and tight (right side of block?). They are not terribly expensive and easy to change if they are not stuck in the block.

Oil light on and temperature light off with a continuous alarm should never happen when the engine is running.

I seem to recall that the low pressure alarm does come on when the key is first turned on (before the engine is started).

If the tilt switch is suspect, it is very easy to access and test. It is controlled by a spring loaded arm connected to a rheostat on the engine mount. Tilt the engine up completely and you should see it (left side?). When the engine is down it pushes the arm down. When the engine is up the spring allows the arm to move up and change the position on the rheostat. The tilt meter is just measuring the voltage coming through this circuit. You can manually move the arm and watch the tilt gauge change to verify it is working.

If the switch is bad or if the arm is broken the engine control module could think you are trying to run the engine while it is tilted out of the water. This should be an intermittent buzzer, about once per second.

I have also seen the alarm come on when continuously when there is a problem with the ground wire in the shifter. When I had this problem I was also not able to turn off the engine with the key. I never tracked down the source of the bad ground.

Good luck. I'm interested to hear what you find out.

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Re: What is causing this alarm on my Honda O/B?'

Post by DaveC426913 » Fri Jul 31, 2020 3:34 pm

Be Free wrote:
Fri Jul 31, 2020 8:38 am
The BF50A is the first generation carbureted engine. There are very limited diagnostics built in. The alarm and lights are for low oil pressure and high temperature. There is no low voltage alarm. A continuous alarm without looking at the lights on the shifter does not tell you what is wrong. You will need to look at the lights on the shifter as well. The factory install had the shifter rotated down 90 degrees which makes the lights very hard to see.
I haven't actually checked the lights on the O/B, only on the shifter. And they were off.

Be Free wrote:
Fri Jul 31, 2020 8:38 am

Both lights off and a continuous alarm is low oil pressure.

Both lights on and a continuous alarm is high temperature.

Oil light off and temperature light on with a continuous alarm is low oil pressure and high temperature.
I will check these over the weekend.
Be Free wrote:
Fri Jul 31, 2020 8:38 am
If you are getting any of these indications and you are SURE that you don't have the indicated problem the sensor is the prime (and cheapest) suspect.
Not sure how to check the oil pressure.
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Re: What is causing this alarm on my Honda O/B?'

Post by Be Free » Sat Aug 01, 2020 8:02 am

"I haven't actually checked the lights on the O/B, only on the shifter. And they were off."

There are no lights on the engine. They are only on the shifter.

"Not sure how to check the oil pressure."

You would have to remove the oil sender and screw in an external oil gauge. That is not something that the average outboard owner would have the test equipent for.

If the engine is running and the oil light is out (should be green) and you are getting a continuous (not on/off once per second) alarm, then the engine thinks that it has low oil pressure. All three have to be happening at the same time. If all three are not happening at the same time then you don't have a low oil pressure alarm and you should ignore everything that follows.

The engine will think it has low oil pressure if the oil pressure is actually low or the oil sender is bad or the wiring for the oil sender is bad or the engine control module is malfunctioning. Any one or any combination of these conditions will make the engine report low oil pressure.

If you have determined that it is in fact a low oil pressure alarm, these are the easiest and least expensive checks to perform in order:

Check your oil level with the engine down. If the engine is tilted up, give it a few minutes for all the oil to drain back into the sump. Remove the dipstick, wipe it off and reinsert it completely. Pull it back out and recheck the oil level. It should be at or slightly above the mark on the dipstick.

Make sure the wire on the oil sender is connected and appears to be making good contact. The oil sender and temperature sender are both on the right side of the engine (under the cover). I'm going from memory here, but I think one has a round connector and the other is flat. Check them both since I don't remember which is which. Look for any damage to the wires. Also look for corrosion or leaking oil.

Replace the oil sender. As long as it is not frozen into the engine, this is an easy and relatively inexpensive process. If I were doing it, I would make sure it was not stuck before ordering a new sender. If it is stuck this is a job for a mechanic. He will have the right tools to get it out without breaking it off in the engine and gauges to properly test the oil pressure.

Beyond that, you should probably take it to a mechanic. Changing the engine control module is not hard, but it is expensive and I would not do it unless I was very sure that was where the problem was coming from.

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Re: What is causing this alarm on my Honda O/B?'

Post by DaveC426913 » Sat Aug 01, 2020 9:06 am

Be Free wrote:
Sat Aug 01, 2020 8:02 am
"I haven't actually checked the lights on the O/B, only on the shifter. And they were off."

There are no lights on the engine. They are only on the shifter.
Ah. I see now. The manual shows configurations for several flavors of motor,
Be Free wrote:
Sat Aug 01, 2020 8:02 am
If the engine is running and the oil light is out (should be green) and you are getting a continuous (not on/off once per second) alarm, then the engine thinks that it has low oil pressure. All three have to be happening at the same time. If all three are not happening at the same time then you don't have a low oil pressure alarm and you should ignore everything that follows.
Engine running: check
Oil light: Dark
Continuous alarm: check
Be Free wrote:
Sat Aug 01, 2020 8:02 am
Check your oil level with the engine down. If the engine is tilted up, give it a few minutes for all the oil to drain back into the sump. Remove the
dipstick, wipe it off and reinsert it completely. Pull it back out and recheck the oil level. It should be at or slightly above the mark on the dipstick.
Oil covers all the way up the dipstick check-pattern.
Be Free wrote:
Sat Aug 01, 2020 8:02 am
Make sure the wire on the oil sender is connected and appears to be making good contact. The oil sender and temperature sender are both on the right side of the engine (under the cover). I'm going from memory here, but I think one has a round connector and the other is flat. Check them both since I don't remember which is which. Look for any damage to the wires. Also look for corrosion or leaking oil.
Does the oil sender go by some other name? There is no such wording in the manual.
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Re: What is causing this alarm on my Honda O/B?'

Post by Tomfoolery » Sat Aug 01, 2020 10:38 am

DaveC426913 wrote:
Sat Aug 01, 2020 9:06 am
Does the oil sender go by some other name? There is no such wording in the manual.
That's because it's a switch, not a sender. It's normally open (NO) and oil pressure above its set point closes the contacts, which grounds the lead. To test the control alarm function, ground the single lead on that switch with a jumper wire. The alarm should go off and the light should go on. See the excerpt from the schematic a few posts up.

https://www.boats.net/product/honda/37240-ZG3-E01

The service manual shows minimum oil pressure with warm oil to be 21.3 psi [1.5 kg/cm^2] at 950 +/- 50 rpm.
Tom
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Re: What is causing this alarm on my Honda O/B?'

Post by DaveC426913 » Sat Aug 01, 2020 11:38 am

Tomfoolery wrote:
Sat Aug 01, 2020 10:38 am
That's because it's a switch, not a sender.
Ah.
'Sender' as in signal. Not 'sender' as in pump.
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Re: What is causing this alarm on my Honda O/B?'

Post by Be Free » Sat Aug 01, 2020 12:36 pm

It may be overly optimistic, but for now let's assume that there is only one fault.

If he pulls the yellow wire off the pressure switch and grounds it to the engine block it should stop the alarm and turn on the light if wiring is good and the ECM is working. This would indicate a bad pressure switch or a bad connection between the wire and the switch.

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Re: What is causing this alarm on my Honda O/B?'

Post by Be Free » Sat Aug 01, 2020 12:42 pm

That's what I get for going from memory. A "sender" provides a varying output, usually a range of voltage. The oil pressure switch is either on or off. Switches control an "idiot light", senders control a gauge. In this case the pressure switch is providing a ground wire for the indicator light and a logical signal to the ECM to use to decide if the alarm should be on or not.

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Re: What is causing this alarm on my Honda O/B?'

Post by Tomfoolery » Sat Aug 01, 2020 1:21 pm

Be Free wrote:
Sat Aug 01, 2020 12:42 pm
That's what I get for going from memory. A "sender" provides a varying output, usually a range of voltage.
Yes, sensors and transducers output voltage in proportion to the pressure, with sensors outputting a mV/V (millivolt output per volt input), and transducers usually output 0.5–4.5V signal, though both also in relation to supply voltage I believe.

Transmitters output 4-20mA in proportion to pressure. Transmitters are less prone to interference than the others, like most 4-20mV signals are, and that’s mostly what we use on hydraulic systems for that reason.

And switches are just binary, on/off devices.
Tom
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