Ignition coil longevity

[tjandrews]

I have a '64 9.5 Johnson that I've owned since 1985. I was just doing my annual Inspection of the Points in anticipation of our annual fishing trip, when it struck me that in all that time I've never replaced the coils. I knew the original owner, dead now, and it's doubtful he ever did it, so those have to be OEM coils.

53 years old, and they look and work like less than 10. Yet I read in this forum about coils going bad in old motors, and I've run across it myself in others.

So why would mine last so long? Blind luck? How long do they usually last?

 

[racerone]

All the coils on a 1964 universal magneto are either cracked or have been replaced.-------Motor I looked at the other day ( 1964 model 9.5 ) had a new set in it.----Post a picture of those coils.

 

[tjandrews]

I looked it up, and I was wrong about when I got the motor. It was in 1984, not 1985. So here are two pics, from different angles. A bit too close on one, so it's a bit fuzzy, but it will do the job. All I know for sure is that *I* haven't replaced those coils, ever. I was going to buy the motor, but after a test run learned that it had a cracked block. The guy, my brother's father-in-law, gave it to me then. I replaced the block with a used one, and went from there. I suppose it's possible that the coils were replaced before I got to it, when the motor didn't run right, but knowing the people involved, it's highly doubtful.

 

[F_R]

Well, ok, lets just say that OMC seemed to change the plastic formula as often as they changed underware. The various colors are clues. The ones you have are one of the most successful formulas, and they still look fine. If they pass a resistance check on the secondary windings (a few k-ohms), run them and enjoy.

 

[racerone]

The condensers appear to be original.

 

[tjandrews]

The condensers appear to be original.

Yeah, I really ought to replace those. Points, too. 30 years or so have worn at least one of the stationary points pretty thin. But it still does the job.

This used to be my main motor on this annual weeklong fishing trip. Used heavily for a week, then pretty much ignored the rest of the year. Now, for the last five years, I've had a '56 15HP Johnson on that boat, a '54 10HP Johnson on my other boat, and this motor goes along as a trip-saving spare. We used it just last year, when the clutch dog in the old 10 started acting up.

 

[gm280]

I would test the condensers and face the points and run it 'til it stops. While that could be tomorrow, or three years from now, that could be the same time span for new parts as well. In other words, if the parts test good, happy boating. JMHO

 

[1kruzer1]

My '65 Johnson 9.5 (owned since '73) still has the original coils. Points and condensers have been replaced, but never the coils. This particular motor has about a bazillion operating hours on it. For a motor that some criticise as being a poor design (they can be tough to work on) this thing has sure been one tough, trouble-free little engine.

 

[tjandrews]

Condensers, at least one of them, need to be replaced. I took the motor along on vacation as a spare, which, as it turned out, we needed. Worked OK for two days, then skipped a bit once or twice but smoothed back out. But then on the way in the next-to-last-day it lost one cylinder completely. We finished the week with just the one boat.

It's possible that I didn't get the screw tight enough, or that the one set of points was worn just too far, but it's not worth the trouble to pinpoint. Condensers are the prime suspect. I still think those coils are OK, though I haven't looked yet.

New parts have been ordered, should be delivered later this week.

 

[gm280]

Condensers, at least one of them, need to be replaced. I took the motor along on vacation as a spare, which, as it turned out, we needed. Worked OK for two days, then skipped a bit once or twice but smoothed back out. But then on the way in the next-to-last-day it lost one cylinder completely. We finished the week with just the one boat.

It's possible that I didn't get the screw tight enough, or that the one set of points was worn just too far, but it's not worth the trouble to pinpoint. Condensers are the prime suspect. I still think those coils are OK, though I haven't looked yet.

New parts have been ordered, should be delivered later this week.

It could be the condenser(s), but I have never ever seen a condenser go back in such an ignition system. But then I haven't worked on OB engines much either. But back in the days when lawn mowers used condensers, I never found a bad one. But replaced a lot just because. JMHO