Electrical Problems

F

fisherkb

New member
This weekend I went to our lakehouse. I took my boat out for a short trip on Saturday afternoon without any incident. I had used my boat two weeks earlier and, like last time, the engine started without any issues. This morning the engine started fine and I left the dock. Shortly after leaving (about 10 minutes) I noticed that my fathometer was flashing weird readings. I stopped - but left the engine idling- and looked to see if the transducer had caught something. Nothing so I went back and noticed when I put the boat back in gear that the tach read 0. I started back home and noticed later that the tach panel eventually went dead altogether and no other electronics would work (engine trim/tilt, fathometer, tach panel, etc.). The engine continued to work fine.

Back at the dock I turned off the engine. I checked for obvious blown fuses and didn't find anything (although not an exhaustive search). I restarted the engine and all appeared okay. I shut it down and tried again. This time all I got was a clicking sound as if the battery was dead. I tried switching to the other battery -- no luck. I didn't have my voltmeter but I did have a simple meter that plugs into a cigarette plug. Both batteries appeared totally dead ~7V each.

I hooked up the charger for a couple of hours. I was able to restart the engine and all the gauges worked. However while I was running the engine I left the battery meter on and noticed, while running, the battery was dropped rapidly in voltage (from 11.6V - only charged for two hours- to 8V). I shut off the engine and noticed the same thing happen when switched to the other battery.

I have two interstate marine cranking batteries since I usually just go out for short trips. I purchased them one and half years ago and I try to keep them charged. I turn off the battery switch when done and I don't have any equipment running when I leave (e.g. a bilge switch). I usually dont run with battery switched to both. It is possible that I did this a couple of weeks ago but I can't recall.

I can't figure out why both batteries drained and how so quickly. At least I think it was quick since I didn't check the voltage before the trips but the engine fired up fine. Also, wouldn't the gauges, etc. continue to function with dead batteries if the engine is running?

My only guess was that my alternator has gone out and that over the last few weeks the batteries have slowly drained out.

I have a 2003 Yamaha 90. I am hesitant to buy two new batteries without troubleshooting more.

I'd appreciate any advice or help. If it is the alternator is there any easy way to confirm? Is the alternator an expense repair?

Many thanks in advance.

Karl
 
Measure the charging voltage with a voltmeter, when the engine is running. It should be ~13.6 VDC. If not there's no charging, the motors alternator is not working Could be the alternator or regulator, though they're often combined into one unit. If the voltage goes to 13.6, the alternator is working..

If that checks OK, charge the batteries with shore power (engine off, battery switch OFF,) and after the charge is complete, let the batteries sit for a couple of days. If they still read ~12.6, the batteries at least can hold a charge, and the problem is in the DC loads. Note that lead acid batteries take a long time to fully charge, at least overnight.

Boris
 
Agree with both above. First go over all connections, take them down, clean them, and put back on tight. Both plus and negative. Agree that it is likely that the alternator/regulator is not working--the tach runs off the alternator in most outboards. There could also be a problem in the regulator which drained the batteries.

At least leave on a charger over night. If you have group 24 batteries they will be about 60 amp hours--to 80 amp hours--and at 10 amps may take up to 24 hours to fully charge (2 x 80 amps equal 160 amps--since they are basically fully discharged.)

The digital volt meter will be key. You will also want to check to see if there is a current draining the battery after fully charged. I have seen cases where a diode blown in the regulator, discharged batteries.
 
Thanks for all the help. I googled the problem a bit. It seems as if there is a known problem with the Yamaha voltage regulator/rectifier on the 2003 models. Looking back I think I recalled a hint of an electrical smell Saturday. Perhaps the voltage r/r went out and caused a short which drained the batteries. I will have to check this out in a couple of weeks when I can get back to my boat. Hopefully there wasn't any further damage and I can replace the voltage r/r/ if that is indeed the cause.

If it is the voltage regulator and the engine runs fine is there likely to be any additional damage or issues? I think I can replace the regulator and then, I guess the batteries, but I want to make sure there isn't a larger issue. Some of the websites mentioned the CDI next the regulator. I'm not sure what this is but I guess I'll find out.

Many thanks for all the helpful hints and recommendations.


Karl
 
Sounds like your rectifier went out and this resulted in a no charging condition...thus the declining voltage until the batteries went dead. The rectifiers that Yamaha used for a while were sized too small...and overheat when lot's of juice is called for in the charging circuit. The original part has been superseded by a much beefier rectifier. Fairly easy change out...see Sunbeams excellent post on the subject:

http://www.c-brats.com/viewtopic.php?t= ... =rectifier
 
Unlikely that if it is just the regulator it caused any other electrical damage, but you do want to check out the alternator output.

Although the battery overall life may be shortened, they may still be OK after charging them up and leaving them on a float charger.
 
Well I got back to the boat. I charged the batteries up and the engine fired up immediately. I checked the voltage before (12.65V) and while running (~9-10V) so I assume that it is the regulator. The regulator looks fine (no obvious charring or burnt parts) but I did not remove it. I chickened out when it came to removing the air intake silencer at the dock. Sunbeam's post is a godsend and sums up exactly the "fear" I had of removing the intake. I am going to order the new voltage R/R. Sunbeam-- did you have any problems with the O-Rings and re-sitting them them? Did you need to completely remove the intake to get to the bolt on the right of the voltage R/R? My boat is at my dock and I have many nightmares of parts going into the abysss!

To all- many thanks for the help and advice. Gotta love this site!

Karl
 
fisherkb":3ougfha6 said:
Sunbeam's post is a godsend and sums up exactly the "fear" I had of removing the intake.
Click to expand...

It does look intimidating, doesn't it.

fisherkb":3ougfha6 said:
I am going to order the new voltage R/R. Sunbeam-- did you have any problems with the O-Rings and re-sitting them them? Did you need to completely remove the intake to get to the bolt on the right of the voltage R/R?
Click to expand...

Hi Karl,

Going from memory here as I'm not with the boat right now:

I never had to get "scary far" into anything (although the parts diagram makes it look like you are about to overhaul the engine!). I also (as was mentioned by Chris) didn't have to completely remove that plastic "manifold" part. I did, however have to loosen all eight (I think it was) of those fasteners. They are the ones that I went back and made arrows pointing to in that other thread. A couple of them were real bears to get to - especially with the limited tools I had on hand. I want to say they were 10mm wrench size, and slipping a wrench over some of them (and then getting it back off again) was a trick. I had couple of different spanners of that size, and one was just skinny enough to fit (I lubricated it with a bit of cursing ;)) I think Chris said he bought a U-joint socket - maybe that would make it easier. I was just about to go try to find some other tool (at a store) when I managed to get them all loosened enough (not that they were so tight, but it's just hard to get a tool in there and turn it).

I didn't drop any parts, but then my boat was sitting on its trailer on land, so of course I didn't.

I loosened the "manifold" (forget the exact name, sorry) just enough to slip it forward enough to get at the blocked fastener of the R/R. I didn't have to take all of the fasteners all the way out, but I did have to manipulate all of them to a certain extent.
 
All,

I thought I'd give an update to my original post. I finally got around to replacing the voltage regulator/rectifier on my 2003 Yamaha 90. There are a couple of lessons from this experience. First, if you need to remove the old V R/R then all you need to is remove the outer plastic cover. Once this is done you can see the VR/R. One screw is behind the air intake silencer. This is the screw that can cause difficulty in removal (see the earlier part of this thread). I found that I could access this screw directly by removing the screen on the air intake and using a 10mm curved box wrench. The key is have a wrench with the right curve to fit behind the silencer. The actual removal is then very simple.

Originally I didn't notice any problem with the old VR/R as the front showed no signs of damage. However, once I removed it I saw that the back of it was completely charred and burnt. I posted a photo in my album (and I will try to include in this post). Apparently the VR/R is a known weak spot for this engine and I found several posts online referring to burnt out VR/Rs and even one that caused a fire significant enough to do further damage to the engine. The new Yamaha replacement VR/R is about 50% larger and has a more substantial heat sink. It is bit pricey (about $200 for the Yamaha original part).

Everything is working fine since the replacement. Thanks again for all that helped me troubleshoot the problem.

Karl

Yamaha_90_Voltage_Regulator.jpg
 
Wow...$200! But at least you did the labor yourself and the new part seems more up to the task. Spooky though as regards the possibility of fire. No bueno...
 
I'm glad you followed up (it's always nice to read how it turns out in the end), and that you were successful in removal/replacement. Those signs of overheating certainly reinforced your having done the right thing! Also, good tip on the easier way of getting in there; I'm going to file that one away (although I have already prophylactically replaced the original R/R on my Yamaha). I bet that will help someone else who's doing it for the first time.
 
Back
Top