1987 85 HP Force motor not charging

[ThePCTech]

This is my first post, I have looked the forum over for help but no direct answer so here goes.

My Force motor runs good but recently seems to have stopped charging. If I charge the battery it will run for a while then just die and not start. It is draining the battery because the depth finder alarms for a dead battery. It does not generate enough electricity to keep itself running.

I have changed the rectifier hoping that it would be a cheap fix, but that did not help. I put a ohms meter on the 2 wires from the stator to the rectifer and it reads .7 to .8. I don't know what it should be I looked at the pdf at outboardignition.com and did not find any measurements to compare it too.

Is it possible that the stator could be bad if the engine is running? Also I replaced the battery with a new one, I have read that the battery should be a serviceable one. Mine has 2 covers each one covering 3 cells. It is a marine starting battery so I would think that is ok.

If you all think that the stator is good is it possible that a circuit breaker popped? Or maybe a bad battery cable? I would think that if either of those were true then it would not start.

Can I check the rest of the stator? If so what should my readings be?

Any help would be appreciated, thanks in advance.

Brian 'ThePCTech'

 

[Jiggz]

The best way to check the charging system is to do what is called a "hot check". Here are the steps.
1. Check voltage battery with engine off. Write it down to the hundreths decimal, i.e., 12.43 or 13.10 volts DC
2. Check the ckt breaker make sure it is not tripped. Depending if you have power T&T you could have two ckt bkrs otherwise there should be one with red and red/white wire on it. To reset just push the little tab in.
3. Make all water connections to prepare to start engine.
4. Start engine and keep it in idle
5. With voltage meter set to read AC voltages, read across the rectifier input terminals, (yellow or yel/grn wires) and you should read around 14~18 Volts AC depending on idle rpm setting.
6. Next set voltmeter to DC and now read the rectifier output terminals, again depending on rpm you should read something above battery terminal voltage that you took in step 1. If not, rev up the motor a little to about 2000 RPM (fast idle) and you should read at least 13~14 volts dc. If you do read this DC voltage then the rectifier is working accordingly.

Caution - do not short any of the terminals at anytime while taking voltages. To do this make sure the meter probes are insulated around except for the pointed ends. Serious damage can occur to the rectifier or even the stator.

Note, force/chrysler motors do not need outside electrical power (except for the starter) to run or keep running. They are designed to be self-powered from the stator power ckt unit which is separate from the charging ckt unit but also physically located in the same stator. The only reason the battery may discharge is due to accessories, i.e. fish finders, gps, radio, etc BUT NOT DUE TO THE MOTOR USING ELECTRICAL POWER FROM THE BATTERY.

 

[ThePCTech]

So what I gather from your statement is that my stator MUST be bad since it will run with a full battery, but if I disconnect the battery while it is running it dies. That would mean that the stator is not generating anything to keep the motor running.

Brian 'ThePCTech'

 

[pnwboat]

I would not assume that the stator is bad with out checking the resistance. You should see 680-850 OHMs between the Blue and Yellow wires that come from the stator and go to the CD Modules. Make sure you disconnect the Blue and Yellow wires when measuring the resistance.

NOTE: Disconnecting the battery will have no affect on the ignition system. Like Jiggz stated, the battery only provides 12VDC voltage to the starter and accessories. The ignition system is self energizing. As soon as the flywheel starts spinning, it generates ignition voltage. You can pull start the motor with a rope without a battery connected and it'll run just fine.

It must have been just coincidence that when you disconnected the battery, the motor died.

 

[ThePCTech]

How hard is it to change the stator? Is there anything I need to know? Any special tools needed?

Brian 'ThePCTech'

 

[Jiggz]

Accessing the stator is the hardest part which involves removing the flywheel. Otherwise, as soon as you removed the stator it is basically a plug and play situation except you also need to re-set the timing. At this point my recommendation is to do more diagnosis, i.e. validate that the stator is actually bad either by doing hot checks or at least cold resistance check. Validate also that your ignition system is still unmodified and should be the Prestolite system and not modified somehow.

 

[ThePCTech]

If I mark the flywheel and put it back on in the same position, will I have to adjust the timing??

Brian 'ThePCTech'

 

[Jiggz]

The flywheel only goes one way into the shaft because it is keyed.

 

[ThePCTech]

So does that mean that I do not have to do the timing??

Brian 'ThePCTech'

 

[jerryjerry05]

If you didn't touch the linkage then NO the timing stays the same.

 

[Jiggz]

So does that mean that I do not have to do the timing??

Brian 'ThePCTech'

No you don't have to do the timing as long as you do not mess with the timing rod and the tower shaft.

 

[jerryjerry05]

Isn't that what I said?

 

[ThePCTech]

The new stator arrives today. I'll let you know how the install goes.

Brian 'ThePCTech'

 

[ThePCTech]

I have been unable to remove the flywheel, that thing is on there, any tips??

Brian 'ThePCTech'

 

[pnwboat]

You need a "puller".

This is the type that I use.



It uses the three bolt holes around the center. Tighten up the 3 bolts, crank down on the center shaft or bolt as hard as you can, then strike the head of the center bolt or shaft with a hammer like you're trying to drive it downwards. The shock will pop the flywheel off. If it doesn't do it on the first strike, tighten the center bolt down some more any try again. Note, you may want to replace the 3 small cheap grade bolts that come with the kit with some high quality grade 8 bolts.

 

[Jiggz]

I'm still not clear why you are replacing the stator. But since the new one is already here . . . I guess you might as well replace it. And yes, as mentioned before removing the flywheel is the hardest part in replacing the stator.

 

[ThePCTech]

Thanks, I'll try that tomorrow morning.

Brian 'ThePCTech'