100 HP Johnson no spark! HELP

[57 7.5]

1972 Johnson 100 hp model number 100ESL72R. I have not checked compression yet but believe it to be good as for when the engine ran it runs like a champ, takes my little 16 ft fish/ski up on plane fast and scoots across the water. But plan to get a tester today and check it. Ok if any of you have been following on my other post I replaced the battery cables per troubleshooting using the CDI guide. And charged the battery 100% last night. Went out this morning connected the battery cables to the battery squeezed the bulb put the choke on and put the control in start and turned the key and it fired right up, was starting to die and I went back and cut the choke off and it picked back up. Got up to the control box to start revving up the engine and it died. Turned the key over and it started again ran a few seconds and died. Turned it over again started and died, tried the fourth time and now it doesn't start. Had my wife turn the key while I had a spark plug out to see if it was getting spark, top left plug no spark and top right plug no spark now. I tested the clipper circuit and rectifier and they are good. I did the first test of the power pack and I believe it's bad, I got .1 aps from terminal block9 to power pack black wire to coil, says should be no more than .7 amps anything higher or low amps it's bad. Is this correct? This motor has ran before then things started going bad, rectifier, clipper circuit (missing), shift diode, shift switch. Replaced all but shift switch (hooked up a toggle switch). Changed spark plugs. I purchased a stator/distributer for a good price off ebay because I think the stator is bad but not sure as I haven't checked it while running. Doing the bench test I believe it's bad. Would that cause no spark?

 

[gm280]

Re: 100 HP Johnson no spark! HELP

Are you absolutely sure it is a spark issue? It sounds like a fuel delivery issue being how it starts and runs for a while and stops. If it is indeed a spark issue, it would be a great idea to trace back from the spark plugs to the ignition coils and points or ignition module. I don't know how your ignition system/setup is built. So start at the very beginning and rule out good parts... Don't just throw money and parts at it to fix it. Do a methodical trouble shooting routine to find the problem(s). Could even be more then one problem, and that is really tuff to locate... JMHO!

 

[57 7.5]

Re: 100 HP Johnson no spark! HELP

Thanks, I'm pretty sure it's spark, it will not start at all now and I had the plugs out grounded to the block while wife turned it over and I didn't see any spark. Will start working backwards and see what I come up with. I really hope its not the power pack. The guy I bought it from said that it was replaced last year but the color of the wires sure don't look new look like original. I'm also trying not to take it to the shop and pay out my you know what to get it running again. My luck it's something little I'm missing and cost me $200 or more.

 

[F_R]

Re: 100 HP Johnson no spark! HELP

Disconnect the coil, unbolt it from the motor, then turn the whole thing to unscrew the spark wire from the distributor. Then remount the coil and connect the primary wire and rig up a spark gap off the spark wire. Now see if you have spark there. That takes that crappy distributor out of the system for a test.

If it is the original pulse pack, I wonder why somebody removed the clipper circuit. It was there to protect the pulse pack.

There is a reverse cut-out ring under the flywheel. It prevents the motor from running backwards (yes, it can). That ring must be serviced. If ignored, it wears out and leaves metal dust all over everything, shorting out the system.

That is not a simple system and worse, few mechanics nowadays understand it. It can be easily damaged. Good luck.

 

[Daviet]

Re: 100 HP Johnson no spark! HELP

If the above information does not help, go back to the CDI website and check your engine using their trouble shooting guide.

 

[boobie]

Re: 100 HP Johnson no spark! HELP

Rapair the forerunner of CDI electronics used to say to get rid of the clipper circuit as it could cause low voltage to the power pack. They also said to keep your battery connections clean and tight. I pulled a lot of those clippers off of motors back in the day.

 

[57 7.5]

Re: 100 HP Johnson no spark! HELP

well I took the boat out this morning to fish, I just fish a marina and a big cove just using the trolling motor. So I got way back in the cove, primed it up put it in start and turned the key and walah it started, so I idled out past the no wake zone and hit the throttle and it got up but not on plane and would not go faster than 7.5 mph per the GPS chart plotter. Ran about a mile down the river and it died, started would idle but not take the throttle, died and then it wouldn't start. So I started fishing back towards the ramp. Fished a cove and tried again and it started wouldn't get out of idle speed after a bit it died again wouldn't start. I finally figured it out, it was getting air in the fuel system somewhere. Stopped on the way home got a bunch of small clamps. I found the culprit hose and I replaced all the spring clamps that were on all the fuel lines with the hose clamps and tightened them down real good and the bulb stays hard and I don't hear any air or have any fuel leaks. Went to try and start it and the battery is completely dead. This has happened before does anyone have an idea what it could be? Would a bad stator cause that?

Thanks GM280 you were right it was fuel delivery. Tomorrow after the battery is fully charged I'll give It a try on the muffs and if the rain misses us i'll take it to the lake and try it out with full load on it

Thanks F R, I'll take a look at the reverse spring, I've been weary of taking off the Flywheel. So I can take the clipper circuit off? I'm pretty sure it's the original power pack, like I said the wires are faded, the purple wire doesn't look purple so unless the guy I got it from put a used one on it's original. It has some kind of coating holding it to the mounting plate/bracket so I can't see it to get any info off of it.

 

[57 7.5]

Re: 100 HP Johnson no spark! HELP

Well she fired up and runs like a champ on muffs and I checked and it's charging the battery too. So once all this rains moves out I'll take her to the lake and take her for a spin. Thank for everyone's help.