Possible bad coils...not sure Johnson 85hp

Hey guys. I was wondering if these symptoms sound like a bad coil/coils. The mechanic just called and told me that my 1976 Johnson 85 hp was running great and that he was done with it. Then he called right back and said it started running on only 2 cylinders for the first time ever... He replaced the rectifier and said that he noticed a coil in it smoking hot and that's when he saw it was running on two cylinders...
Does that sound like a bad coil or maybe a powerpack?? or just a shady mechanic!

Re: Possible bad coils...not sure Johnson 85hp

The spark plug coils are usually pretty reliable-a fairly low failure rate part of the ignition system. Unlikely two of them went at exactly the same moment. I'd look at the power pack first.

Re: Possible bad coils...not sure Johnson 85hp

Thanks for that tidbit. The mechanic now said that he's pretty sure it's my stator... I don't know anything about stators. Would iboats forum gurus agree with that diagnosis based on those symptoms. I guess I'm asking could that possibly be what caused the 2 cylinders to go out at once and the rectifier coil to heat up??

Re: Possible bad coils...not sure Johnson 85hp

Others more knowledgeable than me will chime in but I think I would go get that motor away from that parts changer since he keeps calling back with more expensive parts that it "might" be.

Re: Possible bad coils...not sure Johnson 85hp

Sounds like you have two issues going on. The overheated rectfier and spark on only two cyls. These are typically separate issues. The stator has separate coils to recharge the battery through the rectifier and different coils to provide power to run the ignition system. It is hard to tell anything without knowing some output voltages from your electrical system. I wouldn't recommend changing anything till you know if the stator outputs are out of spec. It could be a bad power pack and a bad rectifier. These parts are all expensive, so some electrical system testing as recommended in the factory service manual is worthwhile and will insure you replace only the parts that are bad.

Re: Possible bad coils...not sure Johnson 85hp

Well I took the suggestions of the previous thread post and took my boat out of there!! When I got it after a month he hadn't done half of the things I had asked him to so now with the help of friends I'm going to do the repairs myself. He said he checked the outputs on the stator and it was not functioning correctly so I went ahead and ordered a used stator online and another used rectifier. I will keep you all posted on progress and if I have any questions during the repair work.
Thanks a bunch guys

Re: Possible bad coils...not sure Johnson 85hp

Ok here's the news...got it home and the stator is FINE according to the Ohmeter specs. While checking it closely, I noticed that 2 of the 4 Ignition coils have inch long cracks in them (only a small gap though). So I am going to go ahead and replace all 4 ignition coils but would those cracks be a reason that the motor spasmodically drops 2 cylinders and other times it runs fine?? Anybody have an opinion?
If those new ignition coils don't fix the problem the only other thing that I can think of is replacing the powerpack...

Re: Possible bad coils...not sure Johnson 85hp

The stator on that model is a two fold component. A series of small coils on both sides are the alternator whose concern is to supply AC voltage to the rectifier which converts that AC voltage to DC voltage to charge the battery.

In the extreme front and rear of the stator are two larger coils that supply approximately 300 AC volts to the powerpack, needed to energize the ignition (spark). Should the stator be leaking a sticky looking substance out of the extreme front or rear section, replace the stator regardless of whatever ohm or voltage reading you may obtain.

The rectifier can be tested easily as follows.

(Small Rectifier Description & Location)
(J. Reeves)

On most 2,3,4,6 cylinder engines, the small rectifier is located on the starboard (right) side of the engine just in front of the engines electrical wiring strip. There are a few older V4 engines that have the wiring strip on the rear portion of the engine and the rectifier would be located just under that terminal strip. The smaller horsepower engines usually have the rectifier located on the starboard side of the powerhead close to the carburetor area.

The rectifier appears to be a round object approximately one inch (1") in diameter and also about one inch (1") high. The base of it is sort of triangular in appearance and is attached to the engine with two (2) screws/bolts..... usually one screw/bolt is larger than the other. The rectifier, depending on which one your engine uses, will have either:

One Red wire, one Yellow wire, and one Yellow/Gray wire, or One Red wire, and two Yellow wires.

Note that either of the above rectifiers could have a fourth wire which would be Yellow/Blue

The coils that have cracks...... This is quite normal with those type coils. Unless you can see sparks jumping from them to ground (crank it over at night with the s/plugs removed), usually those cracks are harmless and cosmetic, in which case coating them with liquid neoprene has been known to exten their life for years.

Now, at the present time, exactly what is your engine doing, how is it acting right now?

Re: Possible bad coils...not sure Johnson 85hp

Great insight in the last post! Thanks. I took off the spark plug wires and turned the motor over a bit in the pitch black and saw no sparks. The rectifier had to be replaced and has been because when the mechanic was running it, he said it dropped 2 cylinders and when it did it overheated the lead wire to the rectifier and it was fried basicly in half. Brand new rectifier. Stator passes tests. Sensor coils pass tests. Should I be more concerned about the old powerpack now rather than the ignition coils as the cause of the dropping of the 2 cylinders...only at high rpms remember and it's temporary (minute or 2) and quite spasmodically meaning it will sometimes crank, shift up fine, and never get to even half speed...while other times it will crank, shift up fine, get to high speeds for a while and then drop 2 cylinders...
I'm worried to take it back out and test run it again until I'm pretty sure it won't fry my new rectifier like what happened to my last one