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1985 Johnson 120hp V4 poor charging battery going dead

ronlong

New member
" Re-posting:

This motor do


" Re-posting:

This motor doesn't seem to be able to keep enough charge in the battery. After running on the lake for awhile and then sitting, it won't turn the starter over.
Last owner put on 2 solar panels to try and keep some charge in the battery.
I'd rather fix the problem.

After a day of running around the lake on a new battery, the voltage (motor off) was 12.4,
voltage (motor running) was 12.3vdc.

Likely a problem?
The battery still starts the motor (for now). "
 
" I has the same problem with

" I has the same problem with a 1986, 200HP Evinrude. My problem was that the rectifier/regulator was blow out. About one hour and $200 later I replaced it myself. "
 
" Where the heck is the rectif

" Where the heck is the rectifier/regulator?
At the rear of the engine at the top, there is a black cover plate with a circuit inside with a clear green epoxy or something. Is that it?
The other little black box by this "cover" appears to be the CD module. "
 
" Ronlong;Replace the regulato

" Ronlong;Replace the regulator/rectifier as per your service manual,if you don't have one get one or take it to your John/Rude dealer for repairs.Next is to loose the wing muts on the battery,use star lockwashers and hex nuts as per factory instructions.Next replace that crappy red Perko battery switch with a good switch ie Cole-Hersee or a Guest,.make sure ALL battery connections are clean and tight. "
 
It is the circuit inside the

It is the circuit inside the clear green epoxy as you described. That assembly is held down by about 6 bolts and there is a heat sink below it that is water cooled inside the engine. The assembly can be removed without pulling the flywheel. I would get a shop manual and test the rectifier per the manual before buying a new rectifier.
 
" Thanks for the info. I have

" Thanks for the info. I have a set of OMC manuals for this engine (from Andrew Menkart of MarineEngine.com)
I will do the test and probably order the part.
Thanks again.

I noticed the stream of cooling water that leaves the engine doesn't flow very hard.

Should this be a fairly hard flow when traveling at top speed?

If it is a problem, where should I start?
I looked at two (pumps?) items above the top two cylinders at the back.
The diaphragms don't look ripped or anything. "
 
" It should be a steady flow o

" It should be a steady flow of water. If weak, the problem is usually the water pump which is located on top of the gearcase requiring removal of the lower unit for access. The two pumps that you referenced are probably the thermostats. "
 
" Hi Ron,

That motor does h


" Hi Ron,

That motor does have its own alternator right? When you put your multimeter on the battery with engine running do you get a -12.3DC voltage reading? Some of the better DC Voltage meters can do that for you. The are not that expensive either. If so that means the regulator/rec. is not working. It doesn't mean its bad though. The engines power source to start is the battery, once its running the magneto takes over and generates the power source to keep it running. Before you buy or pay for anything pull the cowling off. You can see where the battery cables come in the the engine compartment. Follow the red + cable to the starter Check bolts for torque on these connections. Follow the large cables from there and do the same. (You really need a manual) If you have trouble with automotive or small engine repairs also, you have to learn now. Outboard, two cycles, four cycles,ect. I found out that if I could read I could fix engines. I have worked on cars in a garage when I was younger and before that even. The better manuals that have good pictorials especially for someone that is not familiar identifying motor parts can help. Trying to solve problems from information you receive online really can't help you much unless you can identify the regulator/rec., altenator, magento, you know, stuff like that in your engine compartment. The majority of problems with gasoline motors is electrical. If you take care of your motor preventative maintenance, like your car, good fresh gas, the right mfg. recommended oil, winterize, stableize change plugs, impellar (water pump) ect you will still have electrical problems from time to time just from the vibration of the motor and the pounding it gets on that rough water. Your problem may be something you can solve and most times is if you can see the parts in the manual for your motor, identify them when you pull off the cowling, follow and follow the trouble shooting guide in your manual. I get nothing for this but the plesure of passing this information on to others so they don't have to go to the marine service department. The parts are marked up from 100 to 200% so you are still getting overcharged but not paying for the labor. You can fine parts on line at a lot less if you shop and compare prices a little. With any vehicle I have ever owned I buy a shop manual first thing, your can get parts manual for your outboard too. It helps a lot with calling around if you know the part # and don't have to give the counter man all that info on your motor. It will help a good bit by not having to go back to the parts guy 88 times too. If a dummy like me can do this stuff anybody can. Do yourself a big favor bite the bullet, buy a manual for parts and service. You will make yourself crazy trying to solve the problem without it. Hope I helped.
Chuck "
 
" I bought a set of manuals.

" I bought a set of manuals. That has been a great resource.
I tested the rectifier/regulator module and found it to be no good. Diodes were shot and they are all enclosed in epoxy.
I have replaced that module and have enjoyed a wonderful time on the water with no "dead battery" problems at all.
On this same engine, I had some stalling engine problems and had to replace the fuel pump (very expensive). I've had no more problems in that area either.
All my boating time is over now for awhile. I live in Saskatchewan in Canada and my lakes have a couple of feet of ice on them.
Gotta wait until late May 2004 now.
Cheers to all. Seasons greetings. "
 
" Ron,

Glad to hear you hav


" Ron,

Glad to hear you have solved your problems. If I can help any poor consumer to stay out of the marine service department I feel great. That manual is priceless. Me and a lot of other boat owners once felt intimidated by marine engines. I thought it was like working on watch, only a jeweler can do that. I have had a couple of real lemmons with my first two boats. I'm a social worker and one things for sure none or us will ever get rich. After several trips to the marine service shop and the problem not solved, I had no choice but to take up marine mechanics. I would go to this guy he would tell me it was fixed and I'd get on the water and it was the same. You know on top of that, he charged me every time I went back to see him with the same problem that he didn't fix. I didn't know but I became a quick study of marine mechanics policy's. It was a force engine and I will never, ever have another. My wife felt sorry for me because I would go drive two hours to my lake to fish and the motor wouldn't start. After about eight months of seeing me walk in the door with my defeated long face hanging out she said why don't we go to the boat show in a few months and buy a new rig. I didn't try to talk her out of that one, I just her if she would put that in writing. Be sure and change that impeller (water pump) every year. If it is a genuine OMC part and it fails, which means power head replacement, the impeller will warranty your repairs. Doesn't matter that the motor is out of warranty. I do my own but for the warranty purpose you should let the certified OMC mechanic do it. Probably cost you 75-100 bucks but its better than trying to collect from your insurance carrier.
Be safe and watch out for the waverunners.
Chuck "
 
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