Johnson OB Won't Start

[Bill]

Would really appreciate some help from you folks much smarter about OBs than me. I've got a 1989 200hp Johnson that's always been difficult to start. Lately, it's been impossible. A few weeks ago, when it wouldn't start, it turned out that only one cylinder was getting a spark. At that point, I had a Johnson mechanic check out the ob. He checked a number of things, including the magnets on the flywheel. He also rapped on the top of the power pack, and the motor immediately started. Aha! That must have been it, right? Well I bought a new power pack and paid for the installation, and sure enough, it worked like a charm. The motor started immediately every time.

But after only about a week or so, the ob became hard to start again, and soon quit starting altogether.  Rechecked the spark, and now there's no spark at any cylinder. I thought maybe the problem was with the ignition switch/kill circuit, and disconnected the black-yellow wire from the ignition. But there was no change in ob starting (or non-startin in this case). I guess I might have gotten a "bad" new power pack, but am thinking it's probably something else. Does anybody have any ideas? The only test equipment I have is a VOM, but am all ears if anybody has any advice on what to check at this point.

Thanks,
Bill
"Shark Shadow"
1988 22' XF

[GoneFission]

Hit it with a bigger hammer!   :tongue:   Seriously, use your VOM and check to see if you have power to the power pack.  The power pack is often not the problem when there is no spark to any cylinder.  Next check the sender/stator connections - maybe the power pack is not getting a crankshaft signal to trigger the spark.  The power pack would be suspect if those two check out OK.

[John Jones]

make sure there is no corrosion on the power pack connectors.

[Bill]

John Jones: Thanks for your note. The power pack was installed just 2-3 weeks ago, so corrosion probably isn't a problem yet, but I'll double check.

Cap'n John: I like your idea of using a bigger hammer ---- not because it would fix anything, but because after all the trouble the ob has given me, it would feel good to take a hammer to it!  You've given me a lot to work with, but unfortunately, I'm not knowledgeable enough to know how.

-----how do I use the VOM to check the power pack? What contact points or wires (colors) do I use and where are they located? Do I use the meter to see if 12V are being produced when the motor is turning over, or should I be measuring something else?

-----as for the sender/stator connections, are they under the flywheel (please, please tell me I don't have to pull the flywheel!) or somewhere else? Again, can you help with wire colors and locations, and what I should measure?

Hate to be a bother, Cap'n, but thanks in advance for any more help you can give me.

Bill
"Shark Shadow"
1988 22' XF

[John Jones]

John Jones: Thanks for your note. The power pack was installed just 2-3 weeks ago, so corrosion probably isn't a problem yet, but I'll double check.

I had in mind pre-existing corrosion in the motor harness connectors.

[Bill]

John, I understand, and I did double check to be sure, but pre-existing corrosion doesn't seem to be the problem.

 In fact, right now, the problem (whatever it is)  seems to have corrected itself! When I checked the kill circuit originally, I cut the wire at the switch. But this didn't cause the necessary sparking to start again, seeming to indicate that the kill circuit/switch wasn't the problem.  Then a trouble shooting site on the internet said BOTH kill circuit wires should be disconnected back on the motor for a proper test. I did that today, and varooom, the ob started right up! Hot dog! But not one to leave well enough alone, I reconnected one set of wires to see what would happen, and again the motor immediately started. Same thing when I disconnected that set and reconnected the other set. And then to top it all off, I reconnected everything --- should have gone back to no sparking, BUT, no, the ob again started right up.

The only thing that was a little different, and I don't know what it means: some of the time (not always, but often) regardless of what kill circuit wires I had connected/disconnected, when the motor was running, and I turned off the key switch, the ob speed slowed, but didn't go off immediately - it took another 2-5 seconds to go off. It didn't cough like it was starving for fuel. At one point when I had turned the key off and the motor slowed, I turned the key back on (just on, not to crank), and the motor sped up again as it was before I turned the key off.

Clearly I've got an intermittent problem, with just makes it all the more fun trying to figure out what it is.

Bill
"Shark Shadow"
1988 22' XF

[dburr]

If the key switch didn't shut the engine down, I would be MIGHTY suspicious of it...  Motor shop manuals are relatively cheap compared to the $500 you have tied up with the local mechanics.. Grab a book, don't be scared and have at it.. All your wire questions will probably be answered..

You have my condolences , intermittent electrical problems are the worst cause you never really know if you fix them unless you find the smoking wire...

[Bill]

Hey Dave,

Yeah, I don't trust that switch, for sure. The thing is, I seem now to have two problems. According to still another local ob expert, although a bad key switch can cause lots of different problems (including perhaps not immediately stopping the motor when keyed off?), it cannot cause lack of spark to the cylinders except as it affects the kill circuit. And the kill circuit/switch seems to be operating correctly. So I still don't know why I lost sparking to all 6 cylinders or why it came back; and, the motor won't shut off immediately when the key switch is turned off.

I do have a shop manual, and it has helped a bit, but I confess that I get in way over my electrical/mechanical head real quick. Googling 200hp Johnson no spark yields many, many sites, and many have the same symptoms I've got (or had) -  new power pack, etc,  but no spark at any cylinder. The thing is, there's no consensus as to what causes it --- or rather, there seem to be lots of different causes that result in the same problem. Oh well....!

Bill
"Shark Shadow"
1988 22' XF

[flounderpounder225]

Bill
There is a new switch been advertised for weeks on CL here in Pcola, don't know if it's the same style as yours, or of course if it's the problem, and I don't know what they cost new?  But remembered seeing it when I read your latest post... Good luck
Marc

[gran398]

Bypass the switch and jump the starter with a screwdriver. If she fires right up and runs good...you've found the problem.

[Bill]

Hey Folks,

Thanks to all of you who took the time to puzzle through my ob problems and provide suggestions.

I think (THINK!) the problem is resolved. Turns out there was insufficient grounding at the key switch. My best friend came over today and we pretty much went stem to stern checking out contacts, switches, plugs, etc., and found some corrosion, loose plugs,questionable contacts, etc., and corrected them. So the problem of the ob continuing to run after either turning the key off or pulling the kill switch lanyard has been solved. I don't know if the grounding problem could have caused the sparking problem, but think if it was adversely affecting the kill switch directly or via the key switch, it might have. All I know is that the engine is starting at the touch of the key and turning off when it should now. (That's the best it's ever run since I bought it.) Another benefit: my sonar had quit working - false bottom readings or none at all (never mind trying to find fish) - plotter worked, but not the sonar. Well, it's started working again - apparently somewhere along the circuitry, it was suffering from the grounding problem.  (I hadn't even thought of that being involved.)

So I guess what a smart mechanic told me years ago, and many of you alluded to in your replies, is true: always start with the simplest problem/solution and work up.

Thanks again,

Bill
"Shark Shadow"
1988 22' XF

[GoneFission]

Good deal Bill!    Looks like you fixed two problems with one job!