60hp Johnson 3cyl erratic spark

[Dogger CDN]

Hi again. I tuned my 1970 J60ESL70 according to the specs that a OMC guru gave me last week, but I have come up against a problem.<br />When I first tried to fire it up it wouldn't fire, which seemed odd as it never failed to start before tuneup. When I checked for spark there wasn't any. As I was checking out another cylinder suddenly I had spark and everything seemed fine but rough.<br />It sounded like a poor plug set, so I pulled it home to check over on shop spark tester. It showed that the spark was not consistent, and would sometimes quit all togethor killing engine. I checked points again, filed them, and reset them, but didn't really see anything that should have caused erratic spark or shutdown. The only problem noticed was a piece broken out of rotor center ring but that was missing before. I will be replacing it anyway along with e-clips missing on point pivots.<br />While I was doing tuneup I disconnected wire from amplifier to points while I did a compression test. Could this have damaged my amplifier? If it did, I am thinking of changing over to a regular points/condensor/12V coil ignition systm (previous owner already changed box last summer). What condensor would you recommend? <br />I am an automotive/ small engine mechanic so the electrical set-up for this idea is straight forward. Has anybody tried this, and will it work<br />Thanks for any help that can be given.

 

[chunkytrout]

Re: 60hp Johnson 3cyl erratic spark

Having the exact same problem with same motor. Yesterday, had it out again and ran great for an hour. After I shut it down and tried to start it again, no spark. Got it home, put the muffs on and it fired right up. ????

 

[Dogger CDN]

Re: 60hp Johnson 3cyl erratic spark

Hi chunkytrout.<br />I retrofitted my motor over to a regular ignition coil syem today, and all ignition problems disappeared. I used the coil and condensor from a Kohler K341 single cyl lawntractor engine. I wired + terminal of coil to board where purple amplifier wire originally hooked up, then wired white/black stripe wire from points to - terminal of coil, then connected condensor to - terminal of coil and mounted it on coil mounting bolt. The 7mm coil wire threaded out of old coil, crimped on coil wire end, and plugged it into new coil.<br />This new system fired up instantly, and never missed a spark, even when soaked by hose. It even fired two cyinders that I have since found have a poor headgasket, and are sucking water ( but that's a different story )