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Gee Faithful, I'm fulla problems. Have a 1988 Nissan 30 h.p. two cylinder, 2 stroke on my little Whaler. Has run flawlessly from new with just plugs now & then. The other day it started missing when I was idling in and was obviously missing on one cylinder. So I was able to identify the top cylinder as the one misfiring by pulling plug wires one at a time. Put a new set of plugs in and same thing, top cylinder fires some, but sometimes does not. Even switched the bottom and top new plugs to make sure there was not a bad new plug in the mix. Same thing.

Its as though the top cylinder coil is faulty - fires for a few seconds then cuts out, then fires again. Bottom cylinder seems fine. The motor has electronic ignition - a CD/coil module & a new one costs about $225. Guess the only thing I haven't tried is looking at the CD/coil module at night to see if there is perhaps any arcing in the offending plug wire where it comes out of the CD/coil module, or arcing on the body of the unit.

Hate to be a "parts changer" & shuck out for a new CD if something else might do the trick. Y'all got any ideas?

UV

I had a similar problem with the 1980 Johnson 35 on my whaler. New CD fixed it. I don't remember the cost, but it was much less than $225.

Good luck!

Clean the carb.

I know it seems certain to be a coil issue but I would pull apart and clean the carb first. The venturi's clog easily with todays crappy fuel.

I would do that before you spend a dime.

Just my 2 cents.

Should have mentioned the carb - first thing I did - after putting in new plugs - was to pull it and have a buddy who is real good on small carbs pull it down to the last screw & jet - blow it out, Gum-Out it, etc. It was real clean looking but we still took it all the way down.

I also tried gapping down the plug in the cylinder that's misfiring and that didn't do any good which tells me its just just weak, its cutting out.

Yeah, $225 seemed a little steep to me too...I may try the gal in St. Pete that sells used OB parts and see if she has one.

I'd really like to put a Honda on it....Bruce got me a 15 hp years ago for my Goo Boat and its amazing, love the quiet....but they sho' are proud of 'em.

UV

Vic
I had/have a Merc 25 HP that acted the same way.....turns out it was the "Ignition Trigger"......the part was about $85 as I remember.

Back in the Good Ole Days an "Ignition Trigger" was called Breaker Points and cost 6 bucks.....


hb

Harry, that's what's got me worried....I don't really know all the parts in a CD ignition system, but as I understand it, the "trigger" is under the flywheel and feeds the CD module, and I guess there are two of them, one for each cylinder? Is there a way to test the 'triggers'?

Anyway, I can see I probably need to get someone over to the camp to look at it. I gave the trailer to my son since the Whaler lives in slings now...so would have to get it back from him, etc, etc.

UV

Vic
My guess is that there is a way to test them, but I don't know how to do it or what equipment you would need to test it.


I'm not much on electronic stuff.....gimme an old set of breaker points and I can make it work....some how some way.......electronic??.....I'm dumb

I had a local shop fix my Merc when it started skipping, but not before I replaced the Plugs, coils and rebuilt the carb myself. Then the motor sat for a year without being started.

Then I got my little Stauter back from paint guy. Put the Merc on it and made my way all the way up Magnolia River.....shut her down.....not to be started again until another trip to the shop. The mechanic told me that just sitting is not very good on electronic parts.

After replacing the Trigger for the second time....she runs pretty good.

hb

Are the top and bottom coil identical? If so swap. If not then swap the connection and use a spark tester on each at same time to see if bottom coil starts cutting out.

If you eliminate the coils then its either trigger (should only be one) or the stator. If you get your hands on a service manual for that engine it will tell you how to ohm out each of them.

UV

Maybe a bad plug wire?


Peter

As far as I can tell the coil(s) are intergral with the CD module so can't swap them. I suspected the plug wire as the rubber cap that goves over the plug on the offending cylinder was pulled part way off....so took the rubber cap off and the metal clip that hooks to the top of the plug was firmly attached...ran it with the rubber cap off and it did the same skipping. Guess I need to run it at night and look for arcing.

I'll try to run down a service manual.

Thanks,

UV

The triggers are probably magnetic ground switches. You could rig up a test light and battery to test. Need to trace out the wiring fromt he CD to the triggers to isolate. Coils with the CD are probably why it is so expensive. My coils are separate.

When I called the parts place to inquire about the typical life of the CDs they had a good laugh. They fail, without warning (like my plasma TV). They were amazed that I had 30 years on the original (whaler was a tender on a 53...never used much.)

I bought all of my Johnson parts from these guys:

http://www.lmmarine.net/

They are somewhere in the swamps of Alabammy....good folks.

Cam