1974 Mercury 1150 stator issues battery not charging

[bassboy416]

So I've had this problem once before. I own a 1974 Mercury in line 6 1150 that runs fantastic. I have been going through replacing wires like crazy because they were all corroded. A while back the boat left me stranded on the lake. The starter would engage the flywheel but didn't have enough juice to turn it. It was also a brand new battery that had about 4 hours on it the first time. I replaced the starter and a grip of wires and recharged the battery and the problem did not surface again for about 10-15 hours. I had noticed bad wires coming from the stator last time I had the boat home working on it but didn't want to pay for a new stator or replace the flywheel so I just ran the boat. Today I had the same problem happen on the lake. The trim worked fine but the starter was clicking and acting like it had a dead battery. I brought the boat home, charged the battery, and it fired right up. I took the stator off to see if I could splice wires. I tried to read resistance but my meter goes in 20 200 2000 and the manual calls for 1 100 1000. But I did notice the readings were very inconsistent. on 20 I had .5 .6 .7 and it would randomly go to 1 or 0. Here are pictures of the stator and wires.

So two questions. (also keep in mind the tach has worked intermittently but usually does not work since I've had the boat)...
1. Is this likely the cause of my battery draining and in turn the reason my starter won't turn the flywheel?
2. The new stators I am finding online look nothing like this, there is exposed copper on them #174-4793 stator and are really expensive. Do you have any advice of where I can look for a new one and confirm that they are direct fits for my motor as the screw holes need to be correct.

 

[bassboy416]

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I keep trying to post pictures but they aren't showing up... basically the wires are totally shot and the stator is black on the outside with no exposed copper. I don't know why I cna't upload

 

[bassboy416]

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[icebergz12]

I can't comment on the parts being correct or not, but a bad stator or voltage regulator could be the problem. I don't believe the stator is causing a draw but its not charging the battery. The start of the engine every time is the draw. I would do a voltage check at the battery while running check voltage regulator for proper specs. Sorry I'm not more help, but I am unfamiliar with the particular motor.

 

[Georgesalmon]

Erratic tach, signal comes from stator. Battery not charging, voltage comes from stator. Pretty sure you need a new stator. Different manufacturers use different tecniques. You wires are not exposed just covered with a high temp varnish. You can get a new stator that looks different right here on iboats. Just pick the one for your motor. That same stator was used for several years. Last, yup they are expensive.

 

[bilge rat jim]

As suggested by Icebergz, test for voltage at the battery posts while running the outboard at a high idle. You should have a reading of 12.9 - 14.9 VDC. A reading higher than this almost always indicates a failed rectifier. A low reading can indicate a rectifer problem or a stator problem. If you feel that you can splice wires onto your old stator without drastically increasing resistance, give it a try.
You're right about the CDI stator 4973 (yep that's the right one) looking a lot different than the OEM. Most stator failures are due to excessive heat- CDI eliminated the solid epoxy and instead sealed each lobe individually, which allows heat to dissipate easier.

 

[Chris1956]

Bassboy, Your motor has a battery powered CDI ignition. The stator and rectifier combine to charge the battery. The resistance on the stator will be small, but they are pretty tough, and are usually good, if the wiring is intact. The rectifier is usually the weak link. They can short to ground or open. Either of these cause a bad tach operation and no battery charging. I recommend you test the rectifier, and if it is bad replace it.

Charging system testing is easy. Measure battery voltage with the engine off. Now start the motor.. Rev the engine to 1500 RPM or so, and measure battery voltage again. When the engine is running at 1500 RPM, you should have higher voltage then the battery with the engine off.

 

[bassboy416]

UPDATE: I just ordered a rectifier 18-5707 and a stator 174-4793 for my 1974 mercury 1150 376XXXX serial number. The wires to my stator are completely rotten. I have thought about taking my chances and cutting the wires close to the stator and splicing new ones, but they are in bad shape with missing strands and I'm sick of effing with it. I don't know much about the rectifier except that it is a common weak link and when you're spending hundreds on a stator it seems silly not to replace the rectifier as well. I would appreciate any instructions especially pictures of where the rectifier is. I originally thought it was where the stator leads connect but it has 3 posts and now I'm thinking it is over by my switch box on the bottom. Parts should be in this weekend and I should hopefully have a happy ending to this story. thanks for all your help and advice. I failed the tests you suggested and realize something is funky here.

 

[bilge rat jim]

https://www.google.ca/search?q=1974...s%2F404357-1976-mercury-1150-inline-6;640;480

 

[Chris1956]

Bassboy posted a picture of the new version of the rectifier. You may or may not have the new version. The 1973 models (not sure about 1974) had the older style of rectifier. It could be a 3 terminal rectangle, located behind the fuel quick-connect, in the lower cowling. The terminals are plastic and colored red, yellow and yellow. Brown attaches to one of the yellow terminals to power the tach.