Johnson outboard charging system no longer working

[Joolz]

Johnson 115HP model no. J115TLCTE (not sure the year, maybe someone could specify based on the model and pic below?)
Late last year I noticed the battery wasn't being charged anymore. Didn't think this would matter much as I could just charge it at home. But planning a 5 day camping/boating trip for next month with no access to AC, so this could be a real problem for us. Battery is used for my trolling motor during docking and to power the GPS and fish finder. So having a working charging system is now important.

Don't know much about these engines or what could have failed, thus here hoping for input. Posted a pic of a part I suspect could be the issue (indicated with a red arrow in the pic). No idea what it's called. If this is a potential candidate, is there a test I can perform? Have a digital multimetre I could use for Ohm, etc. If additional pics would make this helpful please let me know and I'll post more. Used to replacing alternators in cars but there's nothing here slightly resembling one, so please add detail when describing a part. Thanks.

 

[gm280]

Well Joolz, that very well could be the problem, but there are other things as well that could be the problem as well. You can take a reading of your stator output (AC of course) at the connection of the yellow wires to the rectifier. Read between any two yellow wires to see if you are reading any AC voltage. If you can read AC voltages there and nothing from the red wire to ground (DC voltage), then yes, you have a blown rectifier. But they are available, seems like everywhere. In fact you can get one on here at iboats. JMHO

 

[tblshur]

joolz ,gm280 is spot on . i might add i have the same motor in 140 hp 1983 model also my motor has a clipper , that acts like a voltage regulator very expensive but cdi electronics has a rectifier , (the part you marked) that is a voltage regulator and rectifier combined . same size as your rectifier and about the same price as your rectifier. that is what i put on my motor works perfect .i boats may have the same rectifier. by the way i commend you for a perfectly kept motor beautiful hope this helps :joyous:

 

[Joolz]

Thanks guys, this was very helpful info, had no idea where to start. I did just as instructed and got readings on the yellow wires but nothing on the red. So I removed the rectifier to see if maybe it was a case of a loose wire. Pushed, pulled, twisted, while trying to obtain a reading and nothing. So I think it's pretty safe to say that the rectifier is the problem. Today is a holiday here so will try to locate it locally tomorrow, there's a Johnson parts store in town and I'm sure they'd have one of these. Or depending on the price I may just try what this guy in the link below did (he has the same motor). Apparently it works although I'd be curious to know if anyone else has tried this? He used a cheap bridge rectifier from Radio Shack (or The Source as they're now called in Canada). I'm posting the link here as it describes the testing procedure for those that much like me, had no idea how to run the test: https://www.youtube.com/watch?v=Or9gSDhydA4

tblshur, thanks for letting me know the year of the motor. The boat itself is a 87 (bought it used a couple of years ago). Just replaced the spark plugs on it before the last outing and it runs smoother now. I concur, the motor looks beautiful, although I can see that it could use a bit of lube in some parts. Which lube do you use in parts like the starter, the steering arm and elsewhere? The manual states Johnson Tripple Guard grease but would like to know what alternatives I could use. Next in the roaster is to look at the remote and the throttle control, as it may need adjustment (must push throttle handle all the way forward and it hardly gets up to speed). May have to start a thread on this. Again, thanks to you both for responding and having me on my way.

 

[gm280]

Joolz, yes that will absolutely work if you have only a two wire stator output. And all you have to do is make sure the current and voltage specifications for that bridge rectifier is above what your stator is putting out. It will work all day long.

However, the original rectifiers aren't really that expensive if you want to stay original. I am sure iboats sells them on here as well. JMHO

 

[Joolz]

Good to know, and FYI I'd only be going through the time/trouble of using an alternative to the original if the price disparity is too great. With that said, given how very weak our Can Dollar is compared to the US at the moment, online shopping all of a sudden becomes a lot costlier than it was just a couple of years back. Will definitely compare the prices and if ordering from iboats is reasonable compared to my local prices, I'd be happy to do. Would be nice to support this forum this way. Small way to pay back for all the great advice I get from here.

 

[tblshur]

lpjfg'pi 'PD

 

[Joolz]

No Title

Update: As it turns out the price disparity is huge, enough to justify going the cheaper route. Local Johnson marine store has the oem rectifier for close to $70 once you add taxes. Electronics store near me has a bridge rectifier for $5 Canadian (or some US$3.50 given our horrible current exchange rate). So this was a no brainer. Spent an extra $2 on wire clips and the total was still just a tenth the cost of the OEM part. Tested it and getting a healthy 14.24 volts with the motor in idle. Yay! Not only will this mean a worry-free 5 day boating trip where there is no AC to charge the batteries, but I?ll be able to charge the trailer?s battery while boating. So yeah, thanks to the advice I got here I now have a fully working charging system again and no worries heading out on our backcountry camping/boating trip.

If anyone comes across this post and wants to save a few bucks by doing it this way, here are a few pointers:
- you will need a longer bolt to hold the bridge rectifier in place. You?ll likely already have one of these machine bolts (or in my case, a screw) in your toolbox as these are common. The bridge rectifier has a hole in the middle for this very purpose.

- these get pretty hot, so adding some sort of heat dissipation isn?t a bad idea, as the contact with the motor block is minimal. So I added a couple of large washers, as seen in the pic. Also added thermal paste on the contact points, to better allow for heat transfer. I hope this is enough, will try to update this thread at the end of the season and in years to come. But even if the part fails, it?s only a $5 investment that only takes a minute to replace (literally one bolt/screw to remove). In fact I now plan to buy a spare and leave it in the boat.

- the rectifier I used is rated for 1000 volts and 50A. There are 35A and 25, 22A available. I wouldn?t go less than 20A. Additionally you?d want to purchase wire clips to connect to the new rectifier (use the wires from the old/stock rectifier). You?ll need a short piece of wire for the ground, I used 12 gauge and just wrapped it around the upper bolt where the old rectifier used.

PS: did this in a sunny 30C day, close to 40C inside my portable garage where the boat was. Only took a few minutes and one cold beer - wouldn't have baked myself if this was a big job, in a day like today. Don?t feel guilty having a cold one as I saved enough money to justify buying a couple of cases. So there!

 

[gm280]

Well it sounds like you are good to go. A bridge rectifier is a bridge rectifier regardless how it looks. And since you used one with ample current and voltage capabilities, I see it working for a long time as well. :thumb:

 

[REN3G8]

Google seems to point at a lot of links showing this is an 83 Johnson...

http://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1983&hp=115&model=J115TLCTE

 

[dennis461]

Update: A

...- these get pretty hot, so adding some sort of heat dissipation isn?t a bad idea, as the contact with the motor block is minimal. So I added a couple of large washers, as seen in the pic. Also added thermal paste on the contact points, to better allow for heat transfer. I hope this is enough, will try to update this thread at the end of the season and in years to come. But even if the part fails, it?s only a $5 investment that only takes a minute to replace (literally one bolt/screw to remove). In fact I now plan to buy a spare and leave it in the boat.



the rectifier I used is rated for 1000 volts and 50A. There are 35A and 25, 22A available. I wouldn?t go less than 20A.

Smart repair job...
These type of devices (as you probably already know) are designed to mount to aluminum heat sinks.
The rating, yours is 50A, is at some temperature e.g. 75C, the rating goes lower with higher temps, i suspect without any heat sink, and low current from outboard, the rating still may be suitable.
I see where a DB3500P device is still suitable for 10A at 150C. (And your engine block should never get that high.)

If the washers rust out, look for a aluminum heat sink for around $5.00

 

[Joolz]

Thanks for pointing out that these steel washers will rust out - this isn't something I had considered at the time as I just wanted to get the job done and used what I had at hand. But I concur that it makes sense to use aluminum. I have plenty heat sinks around the house, some loose, some on broken down electronics that I'm sure I could scavenge a heat sink from.

With rust in mind, please answer this: is it common for a bit of water to sit inside the motor while it's running? When I had the cover off and had the motor running with a garden hose to test the new rectifier, I noticed a good half inch of water at the base of the motor. If this is normal, I can totally see why using steel washers to be a very poor choice. I'm now curious if a bit of water sitting inside the engine is normal or does it only happen when running a garden hose to it? Or do I have an issue I need to address?

 

[gm280]

Thanks for pointing out that these steel washers will rust out - this isn't something I had considered at the time as I just wanted to get the job done and used what I had at hand. But I concur that it makes sense to use aluminum. I have plenty heat sinks around the house, some loose, some on broken down electronics that I'm sure I could scavenge a heat sink from.

With rust in mind, please answer this: is it common for a bit of water to sit inside the motor while it's running? When I had the cover off and had the motor running with a garden hose to test the new rectifier, I noticed a good half inch of water at the base of the motor. If this is normal, I can totally see why using steel washers to be a very poor choice. I'm now curious if a bit of water sitting inside the engine is normal or does it only happen when running a garden hose to it? Or do I have an issue I need to address?

I can't say for sure, but I wouldn't suspect any water in the motor housing when it is running. When running it again, look to see where that water is coming from. You may have a gasket that needs replaced. Better to replace such things now then have a problem on the water out away from anywhere. JMHO

 

[Joolz]

Ok, so this confirms that water shouldn't be inside. Next time I have it at the lake will run it for a few minutes, park it and remove the cover to check. One possibility for the water sitting inside was that a garden hose was being used in and perhaps it was just making its way inside due overspray or something. Hopefully I'll have a water-free engine when I do a proper test.

Not to hijack this thread but it occurred to me last night that I should have done a compression test while replacing the plugs. This is something I want to do before I head out again. Anyone knows what the ideal/acceptable PSI is for this motor is? Manual doesn't say. I'd guess above 110 to be acceptable but if someone could confirm that'd be great.

 

[gm280]

Ok, so this confirms that water shouldn't be inside. Next time I have it at the lake will run it for a few minutes, park it and remove the cover to check. One possibility for the water sitting inside was that a garden hose was being used in and perhaps it was just making its way inside due overspray or something. Hopefully I'll have a water-free engine when I do a proper test.

Not to hijack this thread but it occurred to me last night that I should have done a compression test while replacing the plugs. This is something I want to do before I head out again. Anyone knows what the ideal/acceptable PSI is for this motor is? Manual doesn't say. I'd guess above 110 to be acceptable but if someone could confirm that'd be great.

There is no compression figures for any outboard engine that I know about. And yes, usually with an electric start engine 100 PSI or above with all cylinders reading within 10% of each other is what you are looking for. Pull start engines read a little less. JMHO

 

[ondarvr]

I've used the low cost rectifiers for decades to replace the stock ones, so far none of the cheap ones have failed.

 

[gm280]

I've used the low cost rectifiers for decades to replace the stock ones, so far none of the cheap ones have failed.

If you were to dig into the factory model rectifier, you would find the same type diodes that the aftermarket uses. They just assembly the bridge inside the container and epoxy them in place for waterproofing and an assembly the OB manufacture designed and contracted for. The stator and battery don't care what type bridge rectifier they are working with. So a quality after maker type can do the job without any problems as long as they cover the voltage and amperage requirements. JMHO