Charging system problem

[Roy & Dixie]

Monday my wife and I took our newly purchased C-D on a 2 day, overnight cruise through several of the chain of lakes in central Fla. We had taken the boat out once before a few days earlier for a 45nm ride on the St Johns River. We had never hooked a battery charger to either battery since purchase. We assumed the batteries were charging while under way each time. The dash voltmeter read over 12v. We had the selector on both batteries underway, then switched to batt #1 after anchoring. Just before going to bed, I noticed the lights getting dim. I carry a digital voltmeter and measured only 6v on Batt #1. I used Batt #2 to crank up, and realized that the charging system was not working. I decided to save Batt #2 to start the engine the next morning for the trip home. I was surprised the anchor light actually worked all night on the discharged battery. The good battery started the engine the next am, but we could tell it was weak. We came close to being anchored with no way to start the engine. At home I hooked up my battery charger and recharged both batteries. They both seem to hold a good charge.

I am fimilar with how a magneto charging system works. I had to repair that type system on my Vangard powered Cushman Eagle motorbike. Today I located the location of the regulator/rectifier on the front of my 80hp Yahama. It has 3 green wires coming from the stator windings, a red wire to the battery selector switch, and a black ground wire. I disconnected all but the ground wire. I then:
1) measured very low resistance through each of the 3 stator windings.
2) checked that none of the 3 stator windings were grounded.
3) checked that I had 12v from the selected battery to the red wire; thus no blown fuse or loose connection.
4) checked that the black wire was securely connected to ground.
5) I then cranked up and measured @ 24v ac from each of the 3 stator windings at idle RPM.

This leads me to conclude that I have a bad Rect/Reg module. Since a new one will cost me over $100, I want to further verify that the R/R is truly bad. I have a spare module from the motorbike that is designed to hook to only 1 stator winding, 12v, and ground. Is there any reason that I could not temp wire it to the Yamaha using only 1 of the 3 stator windings. I realize I would not get a high charge rate, but with fully charged batteries I would expect to read 14.5v on my dash volt meter with the engine running at a high RPM. Could this cause any problem or damage to any other parts?

[Sunbeam]

This is just a side comment, as you are way out of my league already! However, if you go to replace the rectifier, I'm pretty sure this is the part that C-Brat Chris of Rana Verde said was the only thing he had ever had really go wrong on his 2003 Yamaha 75 (which I believe is basically the same engine as the F80, maybe even the same in all but number).

At any rate, the reason I mention it is that when he went to replace it (if indeed we are talking about the same part - which, if I remember correctly he told me was low down on the front of the motor head), he found that there was a re-designed, more robust part, which is what he put back in. So if you do go to replace it, that might be something to check on (and maybe it would at least give you the satisfaction of being an upgrade from the original, for your money).

Sunbeam

[starcrafttom]

starting on a bad battery. There are several cures for this.
1. I have hand started my honda 90. it comes with a pull rope. You take off the cover place the knotted end of the rope in the slot and wrap the rope around the fly wheel. Then give it a nice pull. Two or three pulls is all it takes and some times just one. Look at your owners manual. I would be suprised if you can't do the same with you yamaha.

2. jump start battery pack. These are cheap and light. Small enough to store on the boat. I used this several times but stopped carrying because pull starting is just to easy.

4. Kicker motor. My nissan kicker had a very large ( for its size ) alternator. We had a whole weekend with a bad battery that would discharge at night. We did not cut short the trip. We just got up and started the kicker ( pull and electric start) in the morning and let it idle while we had breakfast. In a hour it had charged the battery enough to start the main. Not the best thing to do but it works on a short term bases.

[jennykatz]

We have a 06 f-115 that the voltage reg went out and we had no charging this was covered under yamaha's warranty 5th yr into warrantie.The f-115 (1.7L) vs f-80 (1.6L) fuel injected vs carbs but engines are very similar .That seems to be the weak link in the f-115 charging system . I was told not to switch the battery switch while engine is running causes the voltage reg to break down .good luck

[Roy & Dixie]

At any rate, the reason I mention it is that when he went to replace it (if indeed we are talking about the same part - which, if I remember correctly he told me was low down on the front of the motor head), he found that there was a re-designed, more robust part, which is what he put back in. So if you do go to replace it, that might be something to check on (and maybe it would at least give you the satisfaction of being an upgrade from the original, for your money).


Yes, I am sure we are talking about the same part. Thank you for this info on redesign of part. I would be foolish to search for cheaper aftermarket replacement part only to end up buying the older version.

Also, thanks to each of the other posts re: alternate ways to solve a dead battery problem and battery switch change while running. I knew not to ever go to the "OFF" position, but did not think # 1-both-#2 might cause possible problem. No reason to take a chance.

I will post what I observe after I temp hook up the single coil R/R that I have.

[BrentB]

Hi

All good advice

I would check the entire system.

How old are the batteries? If wet cell, check each cell electrolyte level is full and use deionized water. Check the specific gravity of each cell using a battery hydrometer. Check the resting voltage across the pos and neg terminals. Does each battery hold a charge? Then perform a load test. Many places will perform the above for free providing you take the batteries to their shop but it is DIY activity

I would inspect and clean thoroughly each terminal connection on each battery and on the engine, add your favorite protective and tighten the connectors firmly.
I dont use wing nuts on batteries. Instead use flat and lock washers, and hex nuts, and apply a thin film on protective coating. Inspect the cables for signs for deterioration (outer covering cracking, is it flexible?, poor terminal crimps showing bare wire and rust, heat damage seen by discoloration on wire covering). Then move to battery switch

On some Yamaha OBs, the R/R module is water cooled and the water passage can clog and cause poor circulation leading to overheating, erratic operation and module failure.

If you have a Perko switch, operating manuals are located at
http://www.perko.com/catalog/category/battery_switches/

Changing a basic battery switch setting with the engine running is not recommended and other more advance switches are avaible and reasonably priced by shopping online



Best

[thataway]

Good information--and a lot more to come on batteries and charging. Generally just using the outboards will not allow them to charge all of the way up--thus periodically a battery charger is indicated, with the long float charge to bring up that last 15%. I would go thru all of the electrical system, especially on a 13 year old boat--and clean all terminals, put in dielectric grease, and tighten connections. Look for corroded wires also. Maybe up grade the wire. When off the boat, dis connect the batteries.

I always like a digital volt meter on the dash--the analogue are just not accurate enough. The digitals are cheap--even a $12 from WalMart which plugs into the cig lighter is far better than the analogue.

I agree with Tom--some alternate start source--such as the jump start pack

[Roy & Dixie]

Thanks for the additional info and advice. I have just come in from temp hookup of motorscooter R/R to Yahama. As I expected, the charge voltage went up from 13.5v engine off to 15v engine running (this old R/R puts out too much voltage, the reason I replaced it: afraid of blowing head light bulb when voltage reached 15.5v at higher RPM). So I have proven without a doubt that I need new R/R.

[Sunbeam]

[Roy & Dixie]

I would be most grateful if you could report back on your findings vis-a-vis this part on the F80 for future reference.

I will be glad to. I am just about to start shopping online and by phone for the part.

[thataway]

[Roy & Dixie]

Thataway,
My wording was a little confusing. I had the battery hooked up all the time. I had charged the battery overnight so it had a full charge and was reading @ 13.5v before starting the engine. With the temp motorscooter R/R hooked up, I started the engine and watched the dash mounted volt meter increase from 13.5v to 15+v as I increased RPM. It was the first time the charge system had ever shown battery was charging. I am now searching for a replacement part. See the next post from me.

[Roy & Dixie]

I would be most grateful if you could report back on your findings vis-a-vis this part on the F80 for future reference.

The part number for a new R/R for my Yahama F80TLRX is 67F81960-12-00. It is $231.45 online from Yahama parts and $240 from either of two dealers I called. That is double what I expected it to be. A contact that I found said he had a used R/R for my engine, replaced due to some insurance deal. That part number ended in 00-00, not 12-00, and lists new at @ $115. The contact and I concude that the 12-00 is the "improved" version. Better(?) at twice the price. He is researching this for me and I plan to look further into it online. Any dealer will only find the $240 unit so I will be searching online and will post my final results.

[BrentB]

Another source is SIM Yamaha

Email Andy for a price quote at andyjr@shipyardisland.com

I expect he will know the answer to old and new part numbers

[BrentB]

SIM Yamaha has a forum on The HullTruth run by Andy and it is easy to search the archives