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lights burn out when honda outboard in reverse

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geoskup

New member
When I put my 8hp Honda outboard in Reverse and increase the speed, the running lights (and cabin lights) get very bright and then burn-out. What's up?
 
We really need you to provide more info as in the age of outboard, size of battery your using?

It sounds like the regulator/rectifier has a fault but if for instance your trying to run lights straight off the outboards power output without having a battery then that would be the fault as it needs a battery to smooth out any surges of power that you get when throttling up.

There are far more complicated ways of explaining the electrical side of it but I`m just trying to keep it simple.

Matt
 
The Honda outboard has an electric starter built in. It has an internal alternator to charge the battery. There is a heavy 3-pronged cord that plugs into the back of my sailboat. This cord leads directly to the battery. The rest of the electrical system runs off the battery.

This system has been working fine for years. The one think I can think of that may be different this year may be that perhaps I plugged in the 3-pronged connector incorrectly. Although, I would imagine that these connectors are keyed to prevent this from happening. I remember one of the prongs was wider than the other two, but that none of the prongs were angled like I remember in my youth of AC shore connectors. I will inspect the connectors today and see if making this connection icorrectly is even possible to do.

If it were the rectifier, I am assuming this component would be built into my outboard, along with the alternator? Right?
 
OK. I have more information.
I went out to the boat to ensure I had the power plug oriented correctly. Yes, it appears there is only one way to orient the plug, one prong is of a different width.
I then checked the battery power using an ohm meter at the cigarette lighter outlet. It read 11.7 V. I have been trickle charging using a solar panel. I then tried starting the motor with the electric starter. Like all this year, it barely turned the motor over, but it did start after a couple tries. In years past, there was plenty of power to turn over the motor with gusto.
I then let the motor idle, and checked the power again. It read 15V (!) I was somewhat surprised, I thought it should be charging at 13.25V. I then went to increase the RPMS and the motor died. At that point I could not start the motor again with the starter. So I attempted with the manual pull cord. In years past this easily started, but not this year. I pull many times while adjusting the throttle, but to no good. It would not start either way.
I was hoping to run up the RPMS and see what the alternator was putting out. Additionally, I really hoping to put the motor drive into Reverse to see what the alternator was putting out. Since this was the failure mode to start with.
Ugh!
 
geoskup said:
The Honda outboard has an electric starter built in. It has an internal alternator to charge the battery. There is a heavy 3-pronged cord that plugs into the back of my sailboat. This cord leads directly to the battery. The rest of the electrical system runs off the battery.

This system has been working fine for years. The one think I can think of that may be different this year may be that perhaps I plugged in the 3-pronged connector incorrectly. Although, I would imagine that these connectors are keyed to prevent this from happening. I remember one of the prongs was wider than the other two, but that none of the prongs were angled like I remember in my youth of AC shore connectors. I will inspect the connectors today and see if making this connection icorrectly is even possible to do.

If it were the rectifier, I am assuming this component would be built into my outboard, along with the alternator? Right?
Click to expand...

geoskup said:
OK. I have more information.
I went out to the boat to ensure I had the power plug oriented correctly. Yes, it appears there is only one way to orient the plug, one prong is of a different width.
I then checked the battery power using an ohm meter at the cigarette lighter outlet. It read 11.7 V. I have been trickle charging using a solar panel. I then tried starting the motor with the electric starter. Like all this year, it barely turned the motor over, but it did start after a couple tries. In years past, there was plenty of power to turn over the motor with gusto.
I then let the motor idle, and checked the power again. It read 15V (!) I was somewhat surprised, I thought it should be charging at 13.25V. I then went to increase the RPMS and the motor died. At that point I could not start the motor again with the starter. So I attempted with the manual pull cord. In years past this easily started, but not this year. I pull many times while adjusting the throttle, but to no good. It would not start either way.
I was hoping to run up the RPMS and see what the alternator was putting out. Additionally, I really hoping to put the motor drive into Reverse to see what the alternator was putting out. Since this was the failure mode to start with.
Ugh!
Click to expand...

BTW, the motor is a Honda Model BF8D, BFP 8D; the batter is a marine battery (gel?) and is only a couple years old.
 
check the regulator rectifier, charging coil and exciter coil. probably problem in the regulator rectifier,


wajira
 
You must start with the battery FULLY charged and in good shape. A fully charged automotive or deep cycle battery should read 12.6 volts. A little known FACT is that a battery that reads 12 volts exactly is considered to be at only 75% charge. It's a "logarithmic" type thing. Sounds funny but it is true. So, your 11.7 volts puts your battery at being near 50% discharged. No wonder it doesn't want to crank the engine.

IF you can charge the battery and get it to HOLD a charge at 12.6 volts FOR AN HOUR you should STILL have it load tested to see if it may have some sort of internal problem....which....from your story.....I'm thinking it very well may have. Most auto parts stores will test it for you for free.

An INTERNALLY SHORTED battery can damage your outboard's charging system. The fact that you read 15 volts when the engine is running MIGHT indicate that you have damaged the voltage regulator.

IF your current battery FAILS testing...in any way....do NOT hook it back up to your outboards charging system. Get a new battery to do any further testing. A bad battery can ruin your charging system INSTANTLY but a damaged charging system won't hurt the new battery IF you only keep it hooked up briefly for testing. Clean ALL connections for battery and charging system to CLEAN and SHINY before doing anything else. Corrosion on a boat is always a factor and a bad connection can "fool" the charging system into over charging and over HEATING your electrical system.

If you hook a good battery to your outboard and find that the charging volts is OVER 14.6 volts, then the regulator is charging too high and will "cook out" the battery in short order.

Sorry to be so glum but it does not sound good at this point. But, maybe a new battery and clean connections will do the trick.

Good luck.
 
One other thing to add to Jimmy's excellent post - check the cables from the battery to the engine and replace them if you see any internal corrosion. Cut or peel back the insulation near where the wire terminal ends hook to the battery and look for corrosion. If you see any, replace the cables. If not, lay back the insulation, tape it completely, then give it a good coating of liquid electrical tape.
 
Thanks guys. Simply replaced battery and all is good. It was run way down to about 10.6 V. Put a new battery in and checked that the alternator was charging at 14.6V in Neutral, Forward, and Reverse. So far, so good.
 
Well, I would like to hear Jimmy's (JGMO) opinion about that. I don't think just replacing a bad battery is the permanent fix. In my thinking, the low battery should have caused the alternator to output at max voltage and amps, but that power should have been regulated to prevent blowing out lamps and other damage. Jimmy?
 
Well. I would probably be "shot down" by an accomplished EE (electrical engineer) but I don't see this as "unusual". That's why I started my first reply with "make sure the battery is good and fully charged".

The alternator NEEDS the battery for proper operation. It is capable of producing OVER 100 volts D.C. in some "full field" conditions.

The battery is essential to voltage control because it literally acts as a "shock absorber" for the alternator. When the engine starts, if there is enough voltage present to activate the field coil, the alternator will immediately go up in voltage and the entire electrical system will be fed from it. The "set point" for most systems is from 1vdc to 2.5vdc ABOVE battery voltage. MOST are set to the latter. So, again, the battery volts gets the alternator charging and then the alternator takes over and runs everything including replenishing and keeping the battery charged.

If the battery is ALWAYS LOW, and the set point is at 2.5 volts above static level, then, the battery might not get fully charged. This is what usually happens; a battery starts off with a low...11.7v...charge. The engine gets cranked...the voltage in the battery falls to say...9.7v....so, for at least a time, the charging volts are....say 12.2 volts. While this will run the loads on the vessel, it WILL NOT replenish or maintain the battery properly and the battery will remain undercharged. This can get to be a sort of vicious cycle especially if the engine is stopped and restarted frequently and will actually damage the battery making things progressively worse.

As far as the alternator OVER CHARGING and blowing bulbs....If the battery is sufficiently damaged, it may, at some point, go "open circuit" internally. When that occurs, there is now, in an electrical sense, NO battery in the system and the voltage regulator has nothing to reference and might allow the alternator to go "full field" briefly through it's internal "backfeed" circuit. This condition is fairly dangerous for the charging system and will eventually cause alternator, regulator or both to be damaged from this sort of "swelling" and "unswelling" of the charging volts. This happens so fast, the voltmeter doesn't really tell you it's happening. Only an oscilloscope can tell the whole story. The volt meter simply reads a higher than normal "real mean" voltage as the regulator strains to keep things "under control".

So, the battery can go "open" or it can internally "ground out" or what people call a "short" or "short circuit to ground".
This too can cause almost instantaneous "death" to an alternator and is why I always call for a complete battery "health check up" before re installing one that has been giving trouble. It is far better to take it out and charge it...then "stress" test it using the load tester rather than your expensive sail or fishing boat engine as a "test bed".

There. I hope I didn't confuse anyone any worse than I have confused myself.

The point is...an undercharged or bad battery can cause so many symptoms with a charging/starting system, it just makes no sense to come to any conclusions until a KNOWN GOOD battery is in it's place.
 
Last edited:
Ditto to what chawk said.

If it is a gel battery, as he suggests, it may add to the charging pattern complexity.

MIke
 
Well, there is a great "battery analyzer" out there made by Mid-Tronics but it is much too expensive for the average DIYer. It is what many of the auto parts stores use to test batteries these days so taking the battery in for testing works for MOST folks. It is "good" for the battery since it doesn't actually "stress it out" as load testers do. It measures the internal resistance of the battery with a low current transfer technology to determine serviceability. I used one (company purchased) extensively when I ran my truck shop. And, it may be the ONLY tester recommended for GEL cell type or GLASS MAT batteries.

There is an "old school" load tester for wet cell automotive batteries sold at Harbor Freight and other places that uses a resistive "shorting bar" to load the battery. We used those when I was a kid and they worked ok. BUT, they can damage a battery if used improperly and can also hurt you since they get pretty hot.

I have an old Sun VAT 60 with carbon pile that I bought from a closing shop many years ago and it works great too. Very heavy duty and reliable but not very portable and they are getting harder to find.

Here's a China made, light duty tester that is inexpensive and has decent reviews. I'm actually thinking about buying one myself.

http://www.amazon.com/Schumacher-BT...e=UTF8&filterBy=addThreeStar&showViewpoints=0

If anyone has any experience with this one, I would be interested in your opinion.
 
A battery can load test today and crap out tomorrow...nature of the beast....put a new ignition in every 3 years and all will be well...you may be a year or two ahead of the failure but the failure is coming...
 
good write up jgmo....i may add one thing...you mentioned a multi meter not being fast enough to see a rapid fluxuation in voltage....this is made even worse by most digital meters..they average on you....so you may see an attempt by a analog meter to jump etc and never see it on a digital...a good DIGITEC meter is better but they are too expensive for the average home user...
 
Yes, if you have the YENOMs...(money spelled backward) there are some VERY sophisticated "graphing multimeters" that are actually FASTER than some low end DSO's (Digital Storage Oscilloscopes)

I have an OLD analog HEATHKIT Oscope that can show you things IN REAL TIME that a DSO just can't. Actually I should say "lower end" DSO can't.

You are correct...based on my LIMITED knowledge about how these things work, a digital meter does a "sampling" of what is going on. In the AC mode it actually "dumbs down" the info to show you the RMS or root mean square of the sine wave. Because, that "average" is what we are usually only interested in anyway. That's why a good DVOM, like the 87 V Fluke I own, includes an analog bar graph in the display if you want to look at the "humps" or peaks of the wave.

A DSO takes a "snapshot" of what is happening and then plays it back to you micro seconds later. That is the "storage" part of the operation. In the early days of digital, you HAD to have an analog scope around if you wanted "real time" information. But, with faster and faster processing and, again, if you have the money, you can get it digitally today.

I would also agree with you papyson that age SHOULD be a determining factor in deciding where you're going with a battery...ESPECIALLY a lead acid plate type. Modern battery construction allows most of us to often get 5 or 6 reliable years of use out of one in our automobiles AND boats. BUT, as you already stated, I expect the failure rate in the population to increase significantly after 36 months. So, while it is NEVER great to have a battery fail, it can be downright dangerous if it happens when you are a few miles away from shore or help. Something for all boaters to ponder.
 
Now, as I pondered this whole thread and I have a few minutes....
We never fully discussed the fact that the title is; "lights burn out when honda outboard in reverse".

I believe this was part of what might have been bothering chawk_man about the "FIX" being as simple as replacing the battery.

As I consider it, a couple of things come to mind. The first is that, when the outboard is shifted into reverse, it will "torque" and try to pull away from the transom. This typically causes it to pivot "up" slightly and change it's angular relationship to the boat. This change in angle, in turn, could cause some "tugging" to take place on the wiring harness and COULD produce an electrical symptom IF the harness has any defects.

BUT, geoskup reports that all is now well and even states..."charging at 14.6 in "Neutral, Forward and Reverse".

SO, I have to fall back on my damaged battery "theory" and assume that when the boat was moving in reverse, or, possibly, even rocking fore and aft, there was something going on with the battery that had it going open internally and causing havoc with the voltage regulator.

Either that or...there's more to the story that we haven't seen just yet. Hopefully the battery fixed everything and the problem won't return.
 
Yep, that was my hang up, thinking that there was something wrong with the regulator. Likely two different issues, as you seem to acknowledge.
 
It is only logical that the motor charges in forward and discharges in reverse....LOL :)

Sorry....I have been dying to say that.

Mike

Still think the "gel" battery may have had something to do with it, but I have no rationale, like Professor Jimmy has shown on his theories.
 
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