1985 150 hp Johnson v6 Charging Issues Help

[Csasch]

Hi all, hoping to get some advice here. I've looked at all the threads on here about charging issues. I know you want to pull you readings right from the battery. Which I've done and it don't appear the motor is charging the batteries. The readings I get after the motor has been started stay the same as the battery before start, maybe just a bit less, and the battery is charged before hand, and it is new. I do have trim tilt, so yes the reg/ rec is water cooled. My tach works fine and it dosen't appear to be off as to the speed of the motor. It is winter here so the motor/ boat is in storage and finding the readings from the reg/ rec will have to wait. I also know some have stated the motor has to be run a bit before it will charge. Even with this last summer it never appeared to charge. The motor runs great, only issue I've had is at F/T it would hesitate a bit after running, but I found this to be a fuel issue as when I'd squeeze the primer bulb it would solve that problem and I know why so I will fix that when I pull it out of storage. Any thoughts on why its not charging? I'm sure it has to do with the reg/rec or stator but it seems odd the motor runs fine and tach works for this to be the cause.

 

[emdsapmgr]

Re: 1985 150 hp Johnson v6 Charging Issues Help

You are correct, problems with the tach usually means that you have some type of problem with battery charging (the combination rectifier/regulator.) Since your tach functions properly, possible the charging system is functioning normally. You can do some testing to baseline just what is going on. Probably best to check the voltage across the battery, then recheck it once the engine has started, then after it has run for a while. Before starting, a charged battery should be in the 12.5 to 12.6 volt range. If the battery shows only 12 volts after running for a while, that's a problem. The newer combination rectifier/regulators prevent the charging voltage from getting up into the 16+ volts commonly seen on the older systems with the rectifier only. As a result the charging rate is somewhat more subtle. (could be in the mid 13 volt range when running.) Keep in mind that once the engine is started, it runs on it's own internal voltage. Only time it uses the battery (when running) is when the trim is activated. If the starter quickly starts the engine every time, the battery will experience a brief drain, till it is started again. As a result, that engine can run a long time without charging before the residual battery is too low to start the engine. (unless you use the fishfinders and radio a lot, etc...)

 

[Csasch]

Re: 1985 150 hp Johnson v6 Charging Issues Help

First, thank you for your time and reply. You are correct, the battery voltage when charged is roughly 12.5 ish. And I do have a depth finder and a radio hooked up to it. The depth finder dose show battery voltage and after runnning the boat for the day the voltage gets down to the upper 11 range and i never see it increase even while running. This is what led me to think i have a charging issue. The depth finder is hooked directly to the battery. Yes i know that checking with a meter is better and more accurate but you would think I should see it charge there also. Man I hate winter and can't wait to get her out again so I can check things out again!!!! LOL

 

[emdsapmgr]

Re: 1985 150 hp Johnson v6 Charging Issues Help

From your description, it is not apparently charging. It's unusual to have no charging, yet the tach functions normally. One would think the combination rectifier/regulator is the problem. Before you decide to pop for one of these expensive critters, it is worth some of your time to do some add'l testing. I'd check the stator output first. Your factory service manual will tell you how to check it. The stator has two types of coils, one set for making ignition voltage, the other set of coils is to charge the battery. It's this second set that creates the tach signal and the one that I'd double check. The factory manual shows two types of testing for that set of coils: one for current output, the other for ohms. If the charging side of the stator checks out, then I'd be looking at the combination rectifier/regulator again.

 

[Csasch]

Re: 1985 150 hp Johnson v6 Charging Issues Help

Again thanks for your time and thought. Will do when weather permits in about a month or two. Wisconsin is great place to live but winter sucks. :facepalm: LOL Right now I'm a bit ahead of myself because of it, but I thought I'd see if there was anything else I was missing or didn't think of before the time came when I could check these things. I figured it has to be these two things, Reg/ Rec or stator. I'm good with car engines and such, but have limited knowlege of boat engines. I know the basics are the same as far as the engine part goes with the difference of how the charging system works and how the oil is provided to it. When I do get the readings I'll post it. Thanx :joyous: