Stupid question, what effects would a bad spark plug have?

[aristotle]

I'm wondering. What effects will a bad spark plug have on an outboard? <br /><br />I know, stupid question.

 

[KCLOST]

Re: Stupid question, what effects would a bad spark plug have?

If it doesn't fire, no combustion in that cylinder, less power, and some potential wear may occur on the cylinder over an extended period of time. Some may disagree about the wear aspect, but the fuel mix is designed to be burned.

 

[aristotle]

Re: Stupid question, what effects would a bad spark plug have?

Reason I'm asking, because my engine idles fine, and maintains slower speed fine, it sputters on WOT. I spoke with the marine shop and this is what they told me could be the culprit. Thanks, I'll just swap them all out.

 

[aristotle]

Re: Stupid question, what effects would a bad spark plug have?

I also use my motor to troll alot, could have contributed to its deteriation. <br /><br />As a rule of thumb, how often should plugs be changed out? I imagine I have a little over 180-200 hours on this set.

 

[KCLOST]

Re: Stupid question, what effects would a bad spark plug have?

What engine is it?

 

[gss036]

Re: Stupid question, what effects would a bad spark plug have?

If you troll a lot with, it probably has a lot of carbon built up. Do a decarb 1st and start using SeaFoam in you gas. That will help to keep it clean. Changing your plugs are the 1st thing to do after decarbing, that way you will know if that is your problem.

 

[KCLOST]

Re: Stupid question, what effects would a bad spark plug have?

Reason I'm asking, because my engine idles fine, and maintains slower speed fine, it sputters on WOT. I spoke with the marine shop and this is what they told me could be the culprit. Thanks, I'll just swap them all out.

That doesn't sound like a fouling issue, but it may very well be a spark problem of some kind...We need to know what motor you have.

 

[aristotle]

Re: Stupid question, what effects would a bad spark plug have?

It's a 1989 2 stroke Mariner 50hp OB. <br /><br />Now that I think about it, right before I had any problems I had the motor cover off and accidentally dropped my ratchet and it arced on something. Could that have screwed up my starter or some other electrical. <br /><br />What's SeaFoam? Is there a primer somewher eon De-carbing? Relatively easy? <br /><br />I was going to re-build the carbs at first but was advised to try these before I do that.

 

[KCLOST]

Re: Stupid question, what effects would a bad spark plug have?

The starter would not cause a sputtering problem. It only runs when you first start up the motor....<br /><br />You may have injured your switchbox however....<br /><br />Can you check the spark on cylinders while at idle? Do you have a spark gap tester?

 

[aristotle]

Re: Stupid question, what effects would a bad spark plug have?

No, I don't know how nor have a tester. But I'm pretty handy with my hands if you know of somewhere I can check to see how to do it. I just got back from picking up some spark plugs, I'll swap them out and take her for a spin this weekend. If not I'll begin checking out my carbs.<br /><br />Now that I remember it, I think I may have stuck an old spark plug on the lower cylinder because the other one was corroding.

 

[gss036]

Re: Stupid question, what effects would a bad spark plug have?

aristole, go over to yuor closest Schucks Auto Parts store and ask it nd they will all you want. Really only need a couple of cans a year.<br />With 180-200 hours on those plugs, it is probably time for the change.<br />Good luck with your problem.

 

[funpilot]

Re: Stupid question, what effects would a bad spark plug have?

Continuing with the stupid question theme... This makes me wonder, if the spark plug gap on that plug was excessive, would the cylinder pressures at higher RPM cause a sparking problem, leading to a miss at speed?<br /><br />I always felt that big gaps are great for more complete combustion, but small gaps are more reliable, and gaps are specified in consideration of that, along with wear allowance. Thoughts from somebody who really knows what they are talking about (as opposed to my meanderings... lol) would be appreciated.<br /><br />fp