ran outboard with one spark plug disconnected

The nitty gritty: Would it damage an outboard to run it on one cylinder with one of the spark plug wires disconnected?

Background: Earlier this fall I was gifted a ’66 Merc 6hp twin. I brought it up to a friend’s cabin and used it to troll around a small lake on an old rowboat. I was being cautious, first time with the old motor, very old boat, unfamiliar water, etc. The motor ran “OK.” Idle seemed a little rough, but I had no problem trolling around at 2-3 mph. Ran the motor for probably 3 hours total. Never tried to run WOT until it started raining and we wanted to get in quick. Well, quick wasn’t happening. Maxed out at 5mph, would bog down and kill if I twisted the throttle too far. I didn’t think too much of it, figured I would get it sorted out when I had time.

It’s been sitting on an outboard stand in my basement for a few weeks. Popped the cowling off today to start tinkering and noticed right away that one of the 2 spark plug wires was hanging there, completely disconnected. The plugs were brand new. The previous owner had been nice enough to change them out for me, and then forgot to re-connect one of the wires.

That should explain the engine performance; but now I’m worried I messed it up running it like that.

It should be fine

mojogunter wrote:

It should be fine

X2

Phew. Thanks friends! Good to have the piece of mind.

I searched around online but couldn’t come up with anything other than some guy who messed up his Ford Focus running with 1 plug disconnected for 15 minutes. I know an old outboard is a different beast, but I’m a worry wort.

Sure you didn’t pop it off with the motor cover?

My latches in the back can do that with my plug wires if they aren’t stowed away properly.

Than could be a typical sat to long carb issue for the idle and wot.

Edit:Pulling the plug would give you an indication of the situation.

nhamm wrote:

Sure you didn’t pop it off with the motor cover?

My latches in the back can do that with my plug wires if they aren’t stowed away properly.

Than could be a typical sat to long carb issue for the idle and wot.

Well, when he finally got some peace of mind…kaboom! Guess you toasted the “66”…

nhamm wrote:

Sure you didn’t pop it off with the motor cover?

My latches in the back can do that with my plug wires if they aren’t stowed away properly.

Than could be a typical sat to long carb issue for the idle and wot.

Edit:Pulling the plug would give you an indication of the situation.

Hmmmm… No, I’m not “sure.” But I just spent the last 30 minutes TRYING to do it and couldn’t. I’m attaching some photos. IMG_4115 shows the where the cowling lock bracket sits when it’s in “locked” position; IMG_4116 shows it when unlocked to pull the cowling off. There’s a fair amount of clearance between the top of that plug and the bottom of the bracket, it shouldn’t be possible for the bracket to contact the plug at all. I tried moving the plug wire into different and awkward positions, it’s not even possible to get the cowling locked on unless the wire is properly routed outta the way.

Attachments:

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Walleyestudent Andy Cox wrote:

Well, when he finally got some peace of mind…kaboom! Guess you toasted the “66”…

The whiskey is also helping with piece of mind tonight. That and it’s a free motor, so hey, it’s gravy right?

I don’t think anything is toast. It’ll be good to do a nice thorough carb clean anyway, but I still think it’s quite possible the plug was disconnected.

on that old of a motor the worst you could of done is blow out an ignition coil or toast a condenser.
if you find out you still have a misfire,those parts are still available if you did.

if that motor had been new enough you would of most likely fried either the cd box or the trigger,that high voltage has to go somewhere and it will back feed into the ignition system seeking ground.

I would bet its fine,the wire was likely arching to a ground near by.

Thank you sir!

Hey, If iowaboy says it’s fine, it’s fiiiiiiine. Time for more whiskey.

pool2fool wrote:

Thank you sir!

Hey, If iowaboy says it’s fine, it’s fiiiiiiine. Time for more whiskey.
I agree with more whisky !!! dang eelpout guy anyway,( long story lol )

Iowaboy1 wrote:

that high voltage has to go somewhere and it will back feed into the ignition system seeking ground.

You don’t say…… the

nhamm wrote:

<div class=”d4p-bbt-quote-title”>iowaboy1 wrote:</div>
that high voltage has to go somewhere and it will back feed into the ignition system seeking ground.

You don’t say…… the

experience is a great teacher isnt it Nick????

And I think nick’s dealing with something maybe a little more serious than a 6hp Kiekhaefer.

Ha! I’d rather deal with mine all day with a majority of nuts and bolts in that 10-12mm range, have fun with those 6 and 8s and tight spaces!!